CCSD3ZF0000100000001NJPL3IF0PDSX00000001                                      
PDS_VERSION_ID       = PDS3                                                   
RECORD_TYPE          = FIXED_LENGTH                                           
RECORD_BYTES         = 80                                                     
OBJECT               = TEXT                                                   
  PUBLICATION_DATE   = 1994-08-01                                             
  NOTE               = "IMDISP USER'S GUIDE"                                  
END_OBJECT           = TEXT                                                   
END                                                                           
                                                                              
                                                                              
                  USER'S GUIDE FOR THE PDS IMDISP PROGRAM                     
                                                                              
                                                                              
                                 Chapter 1                                    
                                                                              
                                INTRODUCTION                                  
                                                                              
                                                                              
     This document describes version 7.5 of the IMDISP program, an            
interactive image processing utility for the IBM Personal Computer family     
(PC, XT and AT) and compatibles.  It has been developed for use with the      
Compact Disk - Read-Only Memory (CD-ROM) storage systems currently being      
evaluated by the Planetary Data System (PDS). It can also be used to          
display and process images stored on floppy or hard disks.                    
                                                                              
     This User's Guide presents an overview of image processing and CD-ROM    
fundamentals, a section on the installation of IMDISP and CD-ROM software     
and hardware, a description of IMDISP program operation, a description of     
other utility programs which can be used in conjunction with IMDISP, and a    
command summary.                                                              
                                                                              
     Other support software for using the PDS CD-ROM disks has also been      
developed.  These packages include the USGS Planetary Image Cartography       
System (PICS) for MicroVAX computers, a set of FORTRAN routines to access     
CD-ROM disks on VAX computers (VMSCD), and "C" language source code to        
process disks written in the High Sierra format.  Contact Mike Martin         
(JPLPDS::MMARTIN on SPAN) for access to these tools.                          
                                                                              
                                                                              
                                 Chapter 2                                    
                                                                              
                                 BACKGROUND                                   
                                                                              
                                                                              
     Efforts to utilize small computer systems for display and analysis of    
scientific data have been hampered by the lack of sufficient data storage     
capacity to accommodate large image arrays.  Most planetary images require    
nearly a megabyte of storage.  Over the past two years a new storage          
technology, "CD-ROM", has been developed which provides the capability to     
store up to 600 megabytes of data on a single 4.72-inch disk.  The disks      
can be mass produced, and hundreds of copies of large digital archives        
distributed rather than the few sets currently produced.  Readers for         
CD-ROM disks can now be purchased for under a thousand dollars for use on     
personal computers and some science workstations.                             
                                                                              
   The PDS has worked with industry and other government agencies to          
support the development of CD-ROM as a major data distribution and storage    
media for space science data.  Initial development efforts by the PDS, the    
Voyager Project, and multi-disciplinary science representatives have          
resulted in the production of 12 CD-ROM disks containing about 30,000         
images from the Voyager 1 and 2 encounters.  The IMDISP program can be used   
to display most of these data files on a personal computer equipped with a    
CD-ROM drive.                                                                 
                                                                              
   Any feedback on the use of IMDISP is greatly appreciated, and any of the   
following people can be contacted for reporting bugs, adding enhancements,    
etc:                                                                          
                                                                              
      Mike Martin                                                             
      Jet Propulsion Lab                                                      
      Internet: mmartin@jpl-pds.jpl.nasa.gov                                  
      SPAN: JPLPDS::MMARTIN                                                   
                                                                              
      Ron Baalke                                                              
      Jet Propulsion Lab                                                      
      Internet: baalke@kelvin.jpl.nasa.gov                                    
                                                                              
      Archie Warnock                                                          
      Goddard Space Flight Center                                             
      SPAN:     STARS::WARNOCK                                                
      Internet: warnock@stars.gsfc.nasa.gov                                   
                                                                              
                                                                              
2.1 DIGITAL IMAGE PROCESSING SUMMARY                                          
                                                                              
                                                                              
   A digital image is a picture converted to numerical form so that it can    
be stored and used in a computer.  The image is divided into a matrix of      
small regions called picture elements, or pixels.  The rows and columns of    
pixels are called "lines" and "samples", respectively. Each pixel has a       
numerical value, or DN (data number) value, quantifying the darkness or       
brightness of the image at that spot.  In total, each pixel has an address    
(line number, sample number) and a DN value, which is all that the computer   
needs for processing.  The DN value of each pixel usually represents a        
shade of darkness or brightness between black and white (gray levels).  How   
many gray levels there are in an image depends on the number of bits used     
to represent each pixel intensity in the computer.  The number of gray        
levels will be equal to 2^n, where n is the number of bits per pixel's DN     
value.  If 8 bits are used to represent a pixel's DN value (gray level),      
the system will be capable of using 2^8, or 256, gray levels in an image,     
where DN 0 is pure black, and DN 255 is pure white.  If each DN used only 4   
bits of storage, the image would contain only 2^4 or 16 gray levels; if       
there were only 1 bit per DN, the image would contain only black and white    
pixels (bit values of 0 or 1).                                                
                                                                              
                                                                              
2.2 OVERVIEW OF IMDISP CAPABILITIES                                           
                                                                              
                                                                              
   While the specifics of IMDISP commands are discussed in Chapter 4, this    
section provides a general overview of how a user can manipulate images       
once a file is selected.  There are DISPLAY commands which allow the user     
to display all or part of an image at various positions on the display        
screen.  The user may also zoom in and out from a point on the image          
defined by the cursor, and may pan around the image.  The cursor may be       
turned on or off; when on, the arrow keys are used to move the cursor         
around the screen; when off, the cursor is not visible.                       
                                                                              
   A user may choose to "subsample" the image, to enable more or all of the   
original image to be displayed on the screen at once.  For example, if the    
image were subsampled by a factor of 2, every other pixel from every other    
line would be displayed, starting from the upper left corner of the image.    
If a factor of 3 were chosen, every third pixel from every third line would   
be displayed.  Any positive integer may be used for subsampling.              
                                                                              
   The user may produce a histogram of an image file, which is a graph        
showing the number of pixels per DN value, or per range of DN values, for     
the entire image.  Histograms are overlaid on top of the image, but may be    
removed using the REFRESH command.  Subsampling may be specified when         
computing a histogram to reduce the time required for the calculations.       
                                                                              
   A profile may be created which plots DN value versus pixel along a line    
between two points on the image.  After the cursor is used to select the      
two endpoints, the connecting line is drawn on the image and the profile is   
plotted at the bottom of the screen.  There is a plot command to plot the     
actual data values in an image line.                                          
                                                                              
   The user may also "stretch" the image, which is analogous to turning the   
contrast knob on a TV set.  The user specifies low and high DN values; all    
pixels with values lower than the specified "low" become black, and all       
pixels higher than the specified "high" value become white.  All pixels       
between the low and high values are evenly shaded between black and white.    
IMDISP also has several filter functions available.  The user may process     
the image with a convolution filter, mean or median filters.  There is also   
an edge detection filter, as well as functions to brighten, darken and        
smear the displayed image.                                                    
                                                                              
   There are bookkeeping types of commands, also.  These allow the user to    
do such things as retrieve a desired image from the CD-ROM, to save an        
image to a file on hard disk, and to erase only the graphics from the         
screen or to erase the entire screen.  Users may execute batch command        
files to do a series of tasks automatically.  Lastly, the user may, of        
course, EXIT the IMDISP program when done.                                    
                                                                              
                                                                              
2.3 GRAY LEVEL AND FALSE COLOR IMAGES                                         
                                                                              
                                                                              
   Most planetary images are composed of 8-bit DN values representing         
monochrome brightness levels in the scene.  To obtain color images,           
separate images are taken through color filters (red, green, blue) and are    
then combined by ground processing systems to produce a true color image.     
Only a very small fraction of planetary images are available in color         
versions.  Most display and analysis is done on monochrome images.            
                                                                              
   A display with 256 (2^8) gray levels is required to present the            
information contained in a standard image.  However, the human eye can only   
distinguish about 32 gray levels.  Thus 5-bit DN values would satisfy most    
display requirements.  Unfortunately, computers are oriented to the storage   
of and manipulation of items which are a power of two, and 5-bit pixels       
would be very clumsy.  The standard display devices which the IMDISP          
program supports are limited to 16 gray levels (PGA and VGA), 4 gray levels   
(EGA) or 2 gray levels (CGA), but the program also supports several           
"enhanced" VGA display devices offering up to 256 colors (or 64 shades of     
gray).  The 16 gray levels of the PGA are adequate to support image           
analysis; however 4 or 2 gray levels are practically useless for viewing      
planetary images.  Fortunately the EGA display will support 16 different      
colors, and a color palette can be selected which uses a graduated scale of   
colors to represent gray levels, producing a "false color" image (false       
because the displayed color does not represent the actual color of the        
scene).                                                                       
                                                                              
   A false color image (also called a pseudo color image) is created from a   
black and white image by assigning a color (rather than a gray level) to      
each DN value in the image.  For instance, a DN value of 128 could be         
reassigned to yellow if the user so desired.  Ranges of DNs (e.g., 100-125)   
may also be assigned one color.  Pseudo colors get assigned to DN values in   
a pseudo color table, which the display program then uses to determine how    
to color the image on the monitor.  Display programs often have preset        
pseudo color tables with commonly used DN-color combinations, and the user    
can simply call for one of these when generating a pseudo color image.  The   
option exists, of course, for users to generate their own pseudo color        
tables.  Pseudo colors are often used to highlight features of an unusual     
nature in an image.                                                           
                                                                              
   Since the Enhanced Graphic Adapter for the IBM PC provides only 4 gray     
shades (black, dark gray, light gray and white) most image viewing is done    
using a pseudo color table which interprets gray levels as color values       
ranging from black through reds, greens and blues up to white.                
                                                                              
                                                                              
2.4 RADIOMETRIC AND GEOMETRIC CORRECTIONS                                     
                                                                              
                                                                              
   All camera systems have some kind of distortions in the lens, in the way   
the shutter works, etc.  Distortions in the amount of fight transferred       
through the camera to the imaging plate are called radiometric distortions.   
Geometric distortion affects the "squareness" of an image, and is detected    
by taking an image of a geometric grid.                                       
                                                                              
   For spacecraft cameras, both types of distortion can be measured before    
launch, and in a limited fashion, in flight.  These measured distortions      
are saved in digital files.  When a raw image is received, these              
"calibration files," as they are called, are subtracted from (or otherwise    
applied to) the image, effectively removing radiometric and geometric         
distortion.  This process is called radiometric and geometric correction.     
Corrected images contain the closest possible representation of the scene     
being imaged.                                                                 
                                                                              
                                                                              
2.5 IMAGE FILE FORMATS                                                        
                                                                              
                                                                              
   Digital image files are seldom stored as a simple array of pixels.         
Generally there is an area at the beginning of an image file containing       
descriptive information about the image.  This is referred to as a label or   
header area.  Figure 2-1 shows a diagram of a simple image format with a      
label area followed by the image lines.  In practice, images from planetary   
missions have a more complicated format, due to the need to store             
additional information to allow proper interpretation of the image data.      
Figure 2-2 shows the format of a Voyager image, which has engineering         
parameters embedded at the end of each image line to form a line suffix       
area, an engineering trailer record after the last image line, and this is    
followed by an image histogram.                                               
                                                                              
                                                                              
                       --------------------------                             
                         Labels or Header Area                                
                       --------------------------                             
                         Image Array Line 1                                   
                       --------------------------                             
                         Image Array Line 2                                   
                       --------------------------                             
                                   .                                          
                                   .                                          
                                   .                                          
                       --------------------------                             
                         Image Array Line n                                   
                       --------------------------                             
                                                                              
                    Figure 2-1: Simple Image Format                           
                                                                              
   Different image label formats have been developed for use by nearly all    
image processing facilities.  Two formats are widely used within the          
planetary and astronomy communities: the VICAR2 (Video Image Communication    
and Retrieval) labels used by the Multi-Mission Image Processing Laboratory   
(MIPL) and FITS (Flexible Image Transport) labels used for astronomy image    
interchange.  The PDS has developed a label scheme which is very similar to   
these standards, called the Object Description Language (ODL).  This format   
attempts to add a broader range of data descriptive capabilities to the       
proven capabilities of the existing label systems.  A description of the      
ODL architecture is given in Appendix D.                                      
                                                                              
   Most of the images stored on the PDS CD-ROM disks have either ODL or       
VICAR2 labels.  IMDISP will automatically interpret these labels to           
determine the display format of the image data.                               
                                                                              
                 --------------------------------------                       
                   PDS ODL Labels                                             
                 --------------------------------------                       
                   Image Array Line 1    Line Suffix                          
                 --------------------------------------                       
                   Image Array Line 2    Line Suffix                          
                 --------------------------------------                       
                                   .                                          
                                   .                                          
                                   .                                          
                 --------------------------------------                       
                   Image Array Line 800   Line Suffix                         
                 --------------------------------------                       
                   Image Engineering Trailer                                  
                 --------------------------------------                       
                   Image Histogram                                            
                 --------------------------------------                       
                                                                              
                 Figure 2-2: Voyager CD-ROM Image Format                      
                                                                              
                                                                              
2.6 CD-ROM FUNDAMENTALS                                                       
                                                                              
                                                                              
   The CD-ROM disk uses the same basic data storage format as a CD audio      
disk.  In fact, data blocks are identified by minute, second and sector       
number, following the audio format.  Data blocks are recorded along a         
spiral from the inner to the outer radius of the disk.  Each raw data block   
(sector) contains 2,352 bytes of information, with 304 bytes used for         
housekeeping and error correction and 2,048 (2K) containing user data. Each   
data block is called a sector, and 75 sectors are stored per second. Since    
the nominal playing time of a CD disk is 60 minutes, the data storage         
capacity is 75 sectors per second * 60 seconds per minute * 60 minutes or     
270,000 sectors.  Thus the nominal storage capacity of a single CD-ROM disk   
is 540,000 kilobytes, which can be extended to more than 600,000 kilobytes    
and beyond by recording more than 60 minutes of data on a disk.               
                                                                              
   In order to maximize the storage capacity of CD disks a constant linear    
velocity (CLV) recording format is used.  This means that the player          
changes speed (slows down) as it reads from the inside to the outside of      
the disk, to maintain a constant flow of data under the read mechanism at a   
speed of 1.2 meters per second.  This is in contrast to most magnetic disk    
drives which use constant angular velocity (CAV) storage, where the           
information density is greater on the inner tracks that the outer tracks.     
While the use of CLV recording increases the storage capacity of CD-ROM       
disks, it reduces access time, since the disk must change speeds as it        
moves to different positions on the disk radius.  The strategy for locating   
a recorded data block is also more complicated than with constant angular     
velocity recording technology.                                                
                                                                              
   As a result the average access time of CD-ROM drives is between 400 ms     
and 1 s, and the maximum data transfer rate to the host computer is 150       
kilobytes per second.  These rates are approximately an order of magnitude    
slower than magnetic disks.  Therefore, the access mechanisms to disk         
directories and data must be customized for CD-ROM in order to provide        
acceptable performance.                                                       
                                                                              
   The development of a standard logical format for recording data files on   
CD-ROM disks was taken on by a group of CD-ROM applications developers,       
hardware vendors and computer vendors.  The proposed standard resulting       
from this initial effort was called the High Sierra format. This format was   
submitted to the International Standards Organization (ISO) for               
consideration and approved on October 5, 1987. It is now referred to as the   
ISO-9660 standard.  The format used for the early PDS CD-ROM disks is dated   
May 28, 1986, and differs slightly from the final ISO standard.  Microsoft    
and other CD-ROM software developers have committed to supporting this        
preliminary version of the format in later software releases.  However,       
software developed by other vendors to support the ISO format (DEC for        
example) will not support the format of these early disks.                    
                                                                              
                                                                              
                                                                              
                               Chapter 3                                      
                                                                              
                          IMDISP INSTALLATION                                 
                                                                              
                                                                              
   IMDISP requires an IBM PC, XT, AT or 100 percent compatible with 512K of   
base memory.  It supports several graphics display devices, including the     
Enhanced Graphics Adapter (EGA), the Video Graphics Array (VGA), the          
Professional Graphics Adapter (PGA), and the Color Graphics Adapter (CGA).    
The hardware environment in which the program has been developed and tested   
includes and AT class computer, deluxe or enhanced EGA board with 256K of     
memory, selected VGA boards with 512K or 1MB memory, and MultiSync (tm) or    
multiscan monitor.                                                            
                                                                              
                                                                              
3.1 PROGRAM SETUP                                                             
                                                                              
                                                                              
   The IMDISP program can be run from a floppy or hard disk.  To use the      
program from a floppy disk, insert the program disk in the A: or B: drive     
and type the MS-DOS command: "A:" or "B:" to set the floppy disk as the       
default drive.  To use the program from hard disk first create a directory    
to hold the IMDISP files.  Use the MS-DOS command "MKDIR \IMDISP" to create   
a directory to hold the programs.  Use the "CHDIR \IMDISP" command to make    
IMDISP the default directory.  Insert the distribution floppy disk in         
floppy disk drive A:.  Now type "COPY A:*.*" to copy the files from the       
distribution disk to your hard disk.  You should now be able to run all       
examples from that directory on your hard disk.  If you wish to use IMDISP    
from other directories, you need to include the IMDISP directory in your      
MS-DOS "PATH" command.  This command provides MS-DOS with a list of           
directories to search when looking for a program file to run.  If you wish    
to run IMDISP from different directories, the \IMDISP subdirectory should     
be added to the PATH command in your AUTOEXEC.BAT file.  A sample path        
command would look like this:                                                 
                                                                              
                 PATH=C:\DOS;C:\UTIL;C:\WORDSTAR;C:\IMDISP                    
                                                                              
   You may want to add a line to your AUTOEXEC.BAT file which will allow      
you to abort the display program while running batch files or displaying      
large image files.  If the command "BREAK=ON" is placed in CONFIG.SYS, you    
will (sometimes) be able to terminate the IMDISP program by typing the        
control and break keys simultaneously.  Different computer systems offer      
varying response to the control-break command, and the use of this command    
may effect other programs you use.                                            
                                                                              
   You can set IMDISP to start up in the correct display mode for your        
video system by specifying the environment variable IMDISP in your            
AUTOEXEC.BAT file.  A sample command to do this would look like this:         
                                                                              
                            SET IMDISP=ORCHID800                              
                                                                              
if you have an Orchid ProDesigner super VGA board with 512K of video          
memory.  See section 3.3 for a description of all the possible supported      
video modes.                                                                  
                                                                              
   IMDISP also builds various scratch files for use when browsing images or   
executing DOS functions.  By default, they go in the root directory on        
drive C:.  If you wish to have them written somewhere else, you may do that   
by specifying the desired directory in the environment variable IMBROWSE. A   
sample command to do this would look like this:                               
                                                                              
                           SET IMBROWSE=D:\TEMP\                              
                                                                              
This will make IMDISP write its scratch files in the subdirectory TEMP on     
drive D:.  Note that the final backslash (\) is required.  We recommend       
that the drive specified by IMBROWSE have at least 512K of free space - the   
scratch file written when using any of the DOS system calls can be as large   
as that.                                                                      
                                                                              
Also, if you have a collection of color palettes in a separate                
subdirectory, you can specify this directory as being the default palette     
directory.  For example:                                                      
                                                                              
                     SET IMPALETTE=D:\IMAGES\PALETTES\                        
                                                                              
will tell IMDISP to look in the D:\IMAGES\PALETTES directory first when       
loading in a color palette with the PAL LOAD command.                         
                                                                              
IMDISP can use extended memory, managed by an XMS memory driver like          
HIMEM.SYS or QEMM, for its refresh buffer.  If no extended memory is          
available, IMDISP will not set up a refresh buffer by default, but will       
allow the user to open a disk file to be used for refreshing the screen. In   
this case, the environment variable IMREFRESH defines where the refresh       
buffer is to go, so                                                           
                                                                              
                             SET IMREFRESH=G:\                                
                                                                              
tells IMDISP to put the refresh buffer in the root directory of drive G:.     
Note that the refresh buffer can be quite large - a 1024x768 display will     
require 768K of disk space (or XMS memory) to hold the entire buffer.         
                                                                              
                                                                              
3.2 CD-ROM SETUP                                                              
                                                                              
                                                                              
   To use the IMDISP program with PDS CD-ROM disks you will need a CD-ROM     
reader, interface board, and software provided by the vendor which will       
make your CD Reader look like a disk drive to your PC.  The details of        
setting up your hardware and software configuration are beyond the scope of   
this manual, however several aspects of setup will be reviewed.               
                                                                              
   There are many potential pitfalls in setting up your hardware and          
interface board.  Read the directions carefully, and don't assume that        
"default" switch settings are correct.  Check all switches to see that they   
correspond to the recommended settings.                                       
                                                                              
   To work properly with the batch command and label files provided with      
IMDISP, your CD-ROM drive should be set up to be drive letter "L:". Most      
vendor software allows you to select the drive letter which will be           
assigned to the CD-ROM reader.                                                
                                                                              
                                                                              
3.2.1 Microsoft Extensions                                                    
                                                                              
                                                                              
   If you are using the Microsoft Extensions you will load a CD-ROM device    
driver as part of your CONFIG.SYS file (or two drivers if using the Philips   
or DEC readers) with a line like this:                                        
                                                                              
   DEVICE=HITACHI.SYS /D:CDROM1 /N:1                                          
                                                                              
This command assumes that the driver file "HITACHI.SYS"is located in your     
ROOT directory.  The /D:CDROM1 switch assigns a logical name CDROM1 to the    
drive.  A name must be supplied, and is used to identify this device, in      
case more than one CD-ROM drive is being used on your system. The name        
should not be the same as the name of any file stored on your system.  An     
attempt to open a file with the same name as the device driver will result    
in the device driver being opened, not the file.  The /N:1 switch indicates   
that this is drive 1.  This switch is used since some CD-ROM interface        
cards support multiple drives.                                                
                                                                              
   Other commands which should be included in CONFIG.SYS if you are using a   
CD-ROM drive with the Microsoft Extensions are:                               
                                                                              
   LASTDRIVE=Z                                                                
   FILES=30                                                                   
   BUFFERS=50                                                                 
                                                                              
   The LASTDRIVE command tells MS-DOS to allow for enough drive letters to    
support the CD-ROM drive, plus any other drives on your system. Using         
LASTDRIVE=L should also work in most circumstances.  The files and buffers    
specifications provide sufficient system work area to support CD-ROM          
operations.                                                                   
                                                                              
   You must also execute a program called MSCDEX.EXE which allows access to   
the CD-ROM drive as if it were a disk drive on your system.  This command     
can be put in your AUTOEXEC.BAT file so that it is automatically run          
whenever you start-up your computer.  The command format is:                  
                                                                              
   MSCDEX /D:CDROM1 /L:L /M:20 /V /E                                          
                                                                              
   Several MSCDEX command switches are illustrated.  The /L:L command         
assigns the drive name L: to the CD-ROM drive.  The /D switch gives the       
device name of the CD-ROM drive (which must be the same name used in the      
device name parameter of  the "DEVICE=CDROM.SYS" command in the CONFIG.SYS    
file.  The /M:20 switch assigns twenty 2K blocks of memory as a buffer for    
use with CD-ROM data.  The /V switch provides verbose messages when the       
installation program is run, and /E tells the program to use expanded         
memory for the cache area.                                                    
                                                                              
                                                                              
3.2.2 Other Driver Software                                                   
                                                                              
                                                                              
   Some vendors (Reference Technology, TMS) offer CD-ROM software which is    
comparable to the Microsoft Extensions.  Our experience with these software   
packages is that they modify the internals of MS-DOS and may cause            
unpredictable results with your other PC software.  They often do not         
support CD-ROM applications designed to work with the MS-DOS extensions for   
CD-ROM and cannot be used with the IMDISP FILE prompt mode.                   
                                                                              
                                                                              
3.2.3 Problems with CD-ROM Software                                           
                                                                              
                                                                              
   The PDS CD-ROM disks utilize a feature of the CD-ROM format standard       
which provides extended attribute records to define the physical              
characteristics of data files.  These records will be used by VAX and other   
minicomputer systems where the operating system allows a variety of record    
formats (fixed, variable, stream).  Many of the earlier implementations of    
High Sierra software failed to recognize these records, which are placed at   
the beginning of a file's data area.  If your CD-ROM software was developed   
prior to April 1987, it may interpret these records as part of the data       
file, causing the first 2K bytes of each file to appear as meaningless        
binary data.  Users with this problem should contact their hardware or        
software vendors for updated versions of the CD-ROM software.  The IMDISP     
program has been patched to recognize and skip over these records on the      
PDS CD-ROM disks, but these patches may not support other CD-ROM disks with   
extended attribute records.                                                   
                                                                              
                                                                              
3.3 DISPLAY DEVICE CHARACTERISTICS                                            
                                                                              
                                                                              
   IMDISP automatically finds out which display devices are available (PGA,   
EGA, or CGA) and uses the one available.  The Enhanced Graphics Adapter       
must have at least 128K of memory to work properly.  Use of the Color         
Graphics Adapter is discouraged because the pixels have no gray levels,       
only black or white.                                                          
                                                                              
   The display coordinates start at (1,1) in the upper left corner of the     
screen; the line direction is down and the sample direction is to the         
right.                                                                        
                                                                              
                                                                              
3.3.1 Enhanced Graphics Adapter (EGA)                                         
                                                                              
                                                                              
   The EGA is a bit-mapped display device providing a resolution of 350       
lines by 640 samples of 4-bits each.  It produces a digital video signal      
for each primary color (red, green and blue), The video signal for each       
color can be set to one of four levels, roughly equivalent to off, low,       
medium and high.  Thus the number of possible colors (color palette) is 64    
(4^3).  The following table illustrates the colors created by some of the     
different combinations of red, green and blue.                                
                                                                              
      Red=   off, Green=   off, Blue=   off  results in Black                 
      Red=   low, Green=   off, Blue=   off  results in Dark Red              
      Red=medium, Green=   off, Blue=   off  results in Light Red             
      Red=  high, Green=   off, Blue=   off  results in Bright Red            
      Red=   low, Green=   low, Blue=   low  results in Dark Gray             
      Red=medium, Green=   low, Blue=   off  results in Brown                 
      Red=medium, Green=medium, Blue=   off  results in Yellow                
      Red=medium, Green=medium, Blue=medium  results in Light Gray            
      Red=  high, Green=   low, Blue=   off  results in Orange                
      Red=  high, Green=  high, Blue=  high  results in White                 
                                                                              
              Table 3-1: Sample EGA Color Palette Settings                    
                                                                              
                                                                              
   The EGA display is limited to only 16 colors out of the 64 possible,       
because only 4-bits are used to store each pixel value in memory.  This       
4-bit pixel value points to an entry in the color table which represents      
one of the 64 possible combinations of red, green and blue which can be       
displayed.                                                                    
                                                                              
   Many of the newer EGA boards are capable of displaying additional lines    
and samples when using a MultiSync (tm) or Multiscan monitor.  The standard   
EGA uses a 16 Mhz crystal oscillator (something like a clock which            
regulates the display speed), which limits the video output rate to the       
equivalent of 640 pixels by 350 lines.  The EGA circuitry allows for a        
faster crystal oscillator to be added to the board (24 Mhz and beyond)        
allowing about 25 percent more lines to be displayed (480 lines instead of    
350).  A method for adding this capability to an existing EGA board (for      
about $10 worth of parts) is described in the September 16, 1986 issue of     
PC Magazine.                                                                  
                                                                              
   This mode requires that a MultiSync (tm) or multiscan monitor be           
attached to the computer, and there is no way for the program to              
automatically detect the presence of the special monitor.  Therefore this     
display mode is invoked by specifying an MS-DOS "ENVIRONMENT" variable. This  
is done by issuing an MS-DOS "SET" command at the MS-DOS prompt as follows:   
                                                                              
   SET IMDISP=EGA480                                                          
                                                                              
   This command can also be put in your AUTOEXEC.BAT file using a text        
editor, so that you need not invoke it each time you run IMDISP.  It should   
have no effect on other MS-DOS system operations.  There is a chance that     
adding this variable will exceed the size reserved by MS-DOS for environment  
variables.  If so, you should consult your MS-DOS manual to increase the      
environment size on your system.  The environment variable can be removed     
with the MS-DOS command:                                                      
                                                                              
   SET IMDISP=                                                                
                                                                              
where a carriage return is typed immediately after the equal sign. The 480    
line mode requires an additional 83K of memory for the refresh buffer.  If    
you try this mode and receive the message "Insufficient memory for line       
buffer", it is probably because you have a 512K memory machine, or have       
memory resident programs operating (like Sidekick or Superkey) which reduce   
the available memory to less than about 400K. You will need to use the 350    
line mode or remove some memory resident programs to operate in 480 line      
mode.                                                                         
                                                                              
   Users of the EGA with MultiSync (tm) and Multiscan monitors can achieve    
a 16 gray level display through the use of a special device called the        
Grayscaler 1, from Avocado Computer, Box 632, Yorba Linda, Ca, 92686, (714)   
528-1025.  This cable converts the digital video signals produced by the      
EGA board to analog signals.  By selecting appropriate EGA palette entries,   
a fairly good representation of 16 gray levels can be achieved (use the       
palette selection "PAL LOAD GRAY16.PAL" to select this palette).              
                                                                              
                                                                              
3.3.2 Video Graphics Array (VGA)                                              
                                                                              
                                                                              
   This version (5.7) of the IMDISP program includes support for the IBM      
Video Graphics Array (VGA) display device.  The VGA produces an analog        
display with several new color modes.  Of particular interest to IMDISP       
users are the 640 x 480 line mode with 16 displayable colors (or gray         
levels).  The 320 x 200 line mode with 256 displayable colors (or 64 gray     
levels) has been tested but produces very blocky pixels.  This version of     
IMDISP also supports a number super VGA graphic boards (see below).           
                                                                              
   To set the VGA display mode you must set a MS-DOS environment variable     
prior to executing IMDISP.                                                    
                                                                              
   To set the environment variable use the MS-DOS command:                    
                                                                              
   SET IMDISP=VGA                                                             
                                                                              
This will put the display in 640 sample by 480 line mode, with 16 gray        
levels or colors displayable from a palette of 256K.  The display is          
initialized with a gray scale palette, but a pseudocolor palette can be       
invoked with the IMDISP command "PAL PS 0".  The "PALETTE EDIT" command       
will allow you to step forward or backward through the 64 available shades    
for each primary color.  See the next section of the IMDISP manual for more   
information on the palette edit function.                                     
                                                                              
                                                                              
   Users may experiment with the 320 x 200 VGA mode by using                  
                                                                              
   SET IMDISP=VGA320                                                          
                                                                              
The pixels are rather large in this mode, but there are enough colors to      
display images nicely.                                                        
                                                                              
                                                                              
3.3.3 Professional Graphics Adapter (PGA)                                     
                                                                              
                                                                              
   The PGA is a special graphics board developed by IBM for use with          
CAD/CAM applications on the IBM PC.  Because its architecture is              
incompatible with the CGA and EGA boards, it has not been well received by    
software developers.  The PGA provides an analog video signal with a          
display resolution of 480 lines by 640 samples of 8-bits each.  It provides   
16 intensities for each primary color, resulting in a palette of 4,096        
colors (16^3).  The color table allows 256 colors to be displayed             
simultaneously, however only 16 gray levels can be selected.                  
                                                                              
   Use the command:                                                           
                                                                              
   SET IMDISP=PGA                                                             
                                                                              
at the MS-DOS prompt to force IMDISP to go into PGA display mode.             
                                                                              
                                                                              
3.3.4 Color Graphics Adapter (CGA)                                            
                                                                              
                                                                              
   The CGA display is a bit-mapped graphics device with a resolution of 200   
lines by 640 samples of 1-bit each.  It supports only 2 colors in this        
display mode, black and white.  This display can be used to get a general     
idea of the contents of a digital image, or for displaying one bit images     
(graphics for example) but is not recommended for use with the PDS CD-ROM     
images.                                                                       
                                                                              
   To force a multi-function display card into CGA mode, use:                 
                                                                              
   SET IMDISP=CGA                                                             
                                                                              
                                                                              
3.3.5 Super VGA Display Boards                                                
                                                                              
                                                                              
   Several high resolution display boards are supported by this version of    
IMDISP.   Most of them support resolutions with 256 colors or 64 grayscale    
levels.  Select one from the following list if it matches your display        
board:                                                                        
                                                                              
       SET IMDISP=     Resolution     Board Name                              
           ATI640      640x480x256    ATI VGA Wonder Board (512K)             
           ATI800      800x600x256    ATI VGA Wonder Board (512K)             
           ATI1024     1024x768x16    ATI VGA Wonder Board (512K)             
           EVGA512     512x480x256    Everex EV-673 Board  (256K)             
           EVGA640     640x400x256    Everex EV-673 Board  (256K)             
           ORCHID      640x480x256    Orchid ProDesigner+ Board (512K)        
           ORCHID800   800x600x256    Orchid ProDesigner+ Board (512K)        
           ORCHID1024 1024x768x256    Orchid ProDesigner+ Board (1MB)         
           PARADISE    640x480x256    Paradise VGA Board (400 lines if the    
                                      board has 256K of memory)               
           TRIDENT     640x480x256    Trident-based SVGA boards (512K)        
           VESA       1024x768x256    VESA SVGA Interface (1MB) (test)        
                                                                              
                                                                              
3.4 MULTIPLE BUFFERS                                                          
                                                                              
Multiple copies of images (or the entire screen) can now be copied and        
stored away into buffers, limited by the available memory.  If you don't      
have enough memory, the buffers can still be used, but as virtual files       
(see HINTS & TIPS ON CONSERVING MEMORY, down below).  Using the buffers,      
images can now be merged together to create interesting effects.  You can     
add or subtract images from each other.  You can store an image away into a   
buffer before applying a filter, and if you didn't like the result, then      
retrieve it back from the buffer, effectively creating an UNDO feature.       
You can create a "face-on-Venus image" by merging the face-on-Mars image      
with a Magellan image.                                                        
                                                                              
There are 26 buffers available in IMDISP, limited by memory or disk space.    
The buffers are referenced by name as a single letter, one for each letter    
of the alphabet (A-Z).                                                        
                                                                              
                                                                              
3.5 HINTS & TIPS ON CONSERVING MEMORY                                         
                                                                              
If you have no extended memory, or don't have enough extended memory, don't   
despair.  You can still use the buffers if you use the following tips to      
help you maximize the use of the memory                                       
                                                                              
     o IMDISP will automatically create a refresh buffer in extended memory   
       whose size is he size of the screen.  You can disable the refresh      
       buffer and this memory will be freed up for buffer use.  To disable    
       the refresh buffer, type:                                              
                                                                              
           SET REFRESH OFF                                                    
                                                                              
       The refresh buffer can be enabled with                                 
                                                                              
           SET REFRESH ON                                                     
                                                                              
     o IMDISP will also attempt to load an entire image into extended         
       memory whenever you do the FILE command.  You can have IMDISP not do   
       this by using the NOMEMORY option:                                     
                                                                              
           FILE IO.IMG NOMEMORY                                               
                                                                              
     o If you are using a Super VGA graphics card in its highest              
       resolution, then if you switch to a lower screen resolution, this      
       will generally cause the buffers to be smaller.  For example, if you   
       using an Orchid Pro Designer II card in its highest resolution         
       (1024x768), then you can switch to the 800x600 or 640x480 screen       
       resolutions:                                                           
                                                                              
            SET DIS ORCHID800                                                 
            SET DIS ORCHID                                                    
                                                                              
     o Subsample the image so that it doesn't take up the entire screen,      
       which then can be saved to smaller buffers:                            
                                                                              
             DISP SUB 3                                                       
                                                                              
     o Use the FILE option on the COPY or MERGE commands to store buffers     
       into a file instead of extended memory.                                
                                                                              
     o Erase any unused buffers:                                              
                                                                              
              ERASE A                                                         
                                                                              
                                 Chapter 4                                    
                                                                              
                              IMDISP OPERATION                                
                                                                              
                                                                              
   IMDISP can be used to display images up to several thousand lines and      
samples with a variety of pixel formats.  These formats include bit (1        
bit), nibble (4 bits), byte (8 bits), integer (16 bits) or long integer (32   
bits).  Integer pixels may be byte-swapped, which means that the sign and     
most significant 7 bits are in the rightmost byte, and the least              
significant 8 bits are in the leftmost byte.  This is the convention used     
by both the IBM PC and VAX computer hardware families. IBM mainframes and     
68000 series computers (Macintosh and Sun, for example) use un-byte-swapped   
integers.                                                                     
                                                                              
   Program interaction with the user is via commands typed in response to     
the "COMMAND:" prompt.  Most interaction is performed on the graphic          
display screen, and program messages are printed over any image display       
currently on the screen.  The REFRESH command can be used to restore an       
image after other commands have written text over the display.  The ERASE     
command can be used to clear away the clutter left by program status          
messages and previously displayed images.  The screen is not automatically    
erased after each operation in order that multiple images can be displayed    
simultaneously, or so a histogram can be placed on the screen with the        
image.                                                                        
                                                                              
   IMDISP is invoked by typing "IMDISP" or "IMDISP filename", where           
filename is the name of an image file to be opened for processing at          
program start-up.  The filename may include a disk drive and path name        
specification.                                                                
                                                                              
   The program will blank the display screen and display a welcome logo,      
then the prompt "COMMAND:" will appear in the lower left portion of the       
screen.  If a filename is included in the command invocation, the welcome     
message is not displayed and the screen will display the COMMAND: prompt.     
                                                                              
   Typing "HELP" at the command prompt will provide a list of IMDISP          
commands.  The most frequently used commands are "FILE" to open a file for    
processing, and "DISPLAY" to display an image once the file has been          
opened.                                                                       
                                                                              
                                                                              
4.1 COMMAND SYNTAX                                                            
                                                                              
                                                                              
   The command line syntax is of the form:                                    
                                                                              
  COMMAND KEYWORD1 = VALUE1 KEYWORD2=VALUE2 KEYWORD3 VALUE3 ...               
                                                                              
   The command line may be typed in either upper or lower case.  The          
command and the keyword names may be abbreviated to 3 characters in most      
cases.  Any number of spaces may be inserted between words, and the keyword   
and value may be separated by a space or an equals sign.  Some keywords do    
not require a value.  All keywords are optional and have default values.      
                                                                              
                                                                              
4.2 COMMAND DESCRIPTION                                                       
                                                                              
                                                                              
   Table 4-1 presents a summary of IMDISP commands.  They are separated       
into 3 groups, file manipulation commands; display commands and program       
control commands.  Only the capitalized letters are required to specify a     
command.                                                                      
                                                                              
                                                                              
4.3 OPERATING MODES                                                           
                                                                              
                                                                              
   Several of the commands invoke special program operating modes. These      
include the FILE command when issued without a filename argument and the      
CURSOR, PROFILE and PALETTE EDIT commands.  The FILE mode displays a list     
of files in the current directory on the screen for selection.  It also       
contains several subcommands for controlling the display of files on the      
menu screen.  In the CURSOR, PROFILE and PALETTE EDIT commands the cursor     
keys (arrow keys) on the numeric keypad are used in conjunction with other    
keys to control program operation.  These modes are exited by typing either   
a period '.' or carriage return.                                              
                                                                              
File oriented commands:                                                       
                                                                              
    CD or CHDIR .  .  .  .  to change the default directory                   
    DIRECTORY   .  .  .  .  to perform the MS-DOS directory command           
    FILE        .  .  .  .  to specify the name of the image                  
    LABEL       .  .  .  .  to display the image labels                       
    LOG         .  .  .  .  to save (log) commands to a text file             
    SAVE        .  .  .  .  to save the image display to a file               
    TYPE        .  .  .  .  to perform the MS-DOS type command                
                                                                              
Display commands:                                                             
                                                                              
    BROWSE      .  .  .  .  to display a group of images                      
    CURSOR      .  .  .  .  to move the cursor around                         
    DISPLAY     .  .  .  .  to display the image                              
    ERASE       .  .  .  .  to erase the display                              
    HISTOGRAM   .  .  .  .  to display the histogram of the image             
    OVERLAY     .  .  .  .  to place an overlay on the image                  
    PALETTE     .  .  .  .  to adjust the palette for the display             
    PERSPECTIVE .  .  .  .  to plot a pseudo-perspective of the image         
    PLOT        .  .  .  .  to plot image lines and spectra on the display    
    PROFILE     .  .  .  .  to plot a profile of the image                    
    REFRESH     .  .  .  .  to refresh the image plane                        
    SET         .  .  .  .  to set display options                            
    TEXT        .  .  .  .  to draw text on the image                         
                                                                              
Image processing commands:                                                    
                                                                              
    BRIGHTEN    .  .  .  .  to brighten the image                             
    COPY        .  .  .  .  to copy images to/from memory buffers             
    DARKEN      .  .  .  .  to darken the image                               
    ENHANCE     .  .  .  .  to apply various filters to the image:            
         BAALKE                                                               
         CONVOLUTION                                                          
         EDGE                                                                 
         LOG                                                                  
         MEAN                                                                 
         MEDIAN                                                               
         POWER                                                                
         STAIR                                                                
         SMEAR                                                                
         UNSHARP                                                              
    MASK        .  .  .  .  to mask off pixels in the image                   
    MERGE       .  .  .  .  to combine image and memory buffers               
    NEG         .  .  .  .  to invert the color palette                       
    PALETTE     .  .  .  .  to adjust the palette for the display             
    SLANT       .  .  .  .  to slant the image to the right or left           
    STRETCH     .  .  .  .  to do a linear gray scale stretch                 
                                                                              
                                                                              
Program control commands:                                                     
                                                                              
    BATCH       .  .  .  .  to execute a batch command file                   
    EXIT or QUIT.  .  .  .  to exit from the program                          
    HELP        .  .  .  .  Display help information                          
    MENU        .  .  .  .  to select images from a menu file                 
    SYSTEM      .  .  .  .  execute an MS-DOS command                         
                                                                              
         Table 4-1: IMDISP Command Summary                                    
                                                                              
                                                                              
4.4 ERROR HANDLING                                                            
                                                                              
                                                                              
   If an invalid command is issued at the COMMAND: prompt the program will    
beep and return to the COMMAND: prompt.  In handling command parameters the   
program takes action on those parameters that are recognized, but ignores     
invalid parameters.                                                           
                                                                              
   It is also possible for certain system errors to be encountered which      
cause the program to abort leaving your computer in graphics mode.  If you    
are using certain utilities which reset the default text mode screen colors   
(like the Norton Utilities screen attributes command) you may not be able     
to see what is being printed on the screen.  The simplest approach is to      
perform a warm boot, by typing the Ctrl, Alt, Del  keys simultaneously.       
Alternately, you can often type IMDISP then EXIT to reset the computer to     
text mode.  Errors in processing image files on CD-ROM, hard disk or floppy   
disks can cause these aborts.                                                 
                                                                              
                                                                              
4.5 COMMAND REFERENCE                                                         
                                                                              
                                                                              
   This section lists all IMDISP commands alphabetically and describes        
their function, parameters which control  command operation, and provides     
examples of command use, In the command and parameter description the         
following conventions are used:                                               
                                                                              
   filename    represents the name of an MS-DOS file, and may include an      
               optional drive identifier and path specification.              
                                                                              
   n           represents an integer value.                                   
                                                                              
                                                                              
4.5.1 BATCH                                                                   
                                                                              
                                                                              
   The BATCH command reads commands from the specified batch command file.    
If no file name is specified the current directory is searched for a file     
named BATCH.CMD.  The CURSOR, PROFILE and PALETTE EDIT commands should not    
be used within batch command files since they require interactive inputs      
from the keyboard.  Batch files may be nested.                                
                                                                              
   The BATCH command may take the following argument:                         
                                                                              
   filename    filename of batch command file.                                
                                                                              
   A batch file is simply a text file containing a list of commands, with     
each command terminated by a carriage return.  You can add comments to a      
batch file by putting a semi-colon on the line.  Everything from the          
semi-colon to the end of the line is ignored.  If the command file is         
created with a word processor, the program should be used in the              
non-document mode, to assure that carriage returns are embedded between       
command lines.  An example of creating a batch file to display the PDS logo   
image follows.                                                                
                                                                              
   At the MS-DOS command level type:                                          
                                                                              
   COPY CON TEST.CMD                                                          
   FILE LOGO.IMG                                                              
   DISP ZOOM 4                                                                
   DISP ZOOM 2                                                                
   DISP                                                                       
   DISP SUB 2                                                                 
   EXIT                                                                       
                                                                              
   Now run IMDISP and type "BATCH TEST.CMD" at the "COMMAND:" prompt. Make    
sure the file "LOGO.IMG" is in your current directory.  The PDS logo should   
be displayed on the screen in several different sizes.                        
                                                                              
                                                                              
4.5.2 BRIGHTEN                                                                
                                                                              
   The BRIGHTEN command adds a constant value to all pixels in the            
displayed image.  If no value is specified, the default is 10% of the total   
range of DN values (i.e., 2 will be added to all pixels in 16-color modes,    
26 will be added in 256 color modes).                                         
                                                                              
    Examples:                                                                 
                                                                              
       BRIGHTEN                                                               
       BRIGHTEN 50                                                            
                                                                              
4.5.3 BROWSE                                                                  
                                                                              
                                                                              
   The BROWSE command will display all images in a directory one after        
another.  An optional directory mask can be supplied to display only          
selected files ("BROWSE *.IMG").  The command creates a list of files to be   
displayed, then creates and executes a batch command file to display those    
images.  After each image is displayed, the filename is displayed at the      
top of the image.  A BROWSE session can be interrupted by pressing            
control-s, then restarted by pressing control-q TWICE.  A session can be      
halted by typing any other key during the display.  It can then be            
restarted (from the beginning) with the command "BROWSE C:BATCH.CMD". The     
default file name for the batch file created by the BROWSE command is         
'C:BATCH.CMD'.  This name can be changed using the "SET BROWSE fname"         
command where fname can consist of a drive letter and filename, which         
should be terminated  with the extension ".CMD".  It can also be set from     
DOS or in your AUTOEXEC.BAT file by using the environment variable            
IMBROWSE.   For example, the DOS command                                      
                                                                              
   SET IMBROWSE=D:\TEMP\BROWSE.CMD                                            
                                                                              
will make the create the BROWSE command file in the subdirectory TEMP on      
drive D:.                                                                     
                                                                              
   The BROWSE command has one argument and several optional keywords.         
                                                                              
   fname         optional file selection mask (must immediately follow the    
                 command BROWSE).                                             
                 Examples: *.img, D:\IMAGES\*.IMG, L:*.BRS.                   
                                                                              
   SIZe n        allows the display of multiple images on the screen.  For    
                 example, on a 640x480 VGA display, six 200x200 images can    
                 be displayed adjacent to each other.                         
                                                                              
   SUBsample n   used in conjunction with the SIZE command, to scale each     
                 image to fit in the SIZE specification.  Same as SUB         
                 option used with the DISPLAY command.                        
                                                                              
   NOLabel       inhibits writing the file name label at the top of each      
                 image as it is displayed.  The default is that labels are    
                 enabled.                                                     
                                                                              
   DNLow DNHigh  sets the DN range for all images (see SET).                  
                                                                              
   PAUse n       pauses display for n seconds when the screen gets full.      
                                                                              
   ALL           searches all subdirectories in addition to the current       
                 directory, looking for files matching the mask.              
                                                                              
   AUToset n     sets DNLO adn DNHI to n% of the full range, based on the     
                 image histogram.  The default is 5%.                         
                                                                              
   SELect        interactively selects files as they are being displayed      
                 and writes the filenames out to a "select" file. The         
                 default select file is "C:\IMDISP.SEL" and this can be       
                 changed by using the SET SELECT command.                     
                                                                              
   FILe fname    select files to browse from a file instead of using a        
                 mask.  The file will contain a list of files, and the list   
                 can have wildcarded names.  The filename can also be the     
                 IMDISP.SEL file created earlier with the SELect option.      
                                                                              
   BUFFERS       browses through all the memory buffers which have been       
                 created.                                                     
                                                                              
   EXAMPLES:                                                                  
                                                                              
       BROWSE *.* SIZE 200 SUBSAMPLE 4                                        
                                                                              
will display all the files in the current directory, subsampling each by 4    
and displaying them in a 200 x 200 window.  The command:                      
                                                                              
       BROWSE *.IBG SIZE 100 SUB 2 PAUSE ALL                                  
                                                                              
when used with the Voyager browse images will display all of the browse       
images on the screen (including the subdirectories), pausing each time        
the screen fills up with images.                                              
                                                                              
       BRO *.* SIZE 200 ALL SELECT NOLABEL                                    
                                                                              
will allow the selection of individual images and                             
                                                                              
       BRO FILE C:\IMDISP.SEL SIZE 200                                        
                                                                              
will redisplay the images that you just selected.                             
                                                                              
       BROWSE BUFFERS PAUSE                                                   
                                                                              
displays the contents of each buffer, pausing in between each display.        
                                                                              
       BRO BUFFERS SIZE 100 SUB 4                                             
                                                                              
displays a small version of each buffer.                                      
                                                                              
*** NOTE ***                                                                  
                                                                              
   BROWSE does not distinguish between image and non-image files, and it is   
up to the user to provide the appropriate directory mask to select ONLY       
images.  If a message "Image does not have proper label" comes up on the      
screen during BROWSE, it is probably because a non-image file is in the       
directory you are browsing.   You can type carriage returns several times     
to get back to the "COMMAND:" prompt, and the browse will continue.           
                                                                              
   If you are using BROWSE on a computer without a hard disk, you will have   
to use the SET BROWSE command to change the default browse file name to a     
writable disk drive,  for example: "SET BROWSE A:BROWSE.CMD". If you are      
using BROWSE to view files on a CD-ROM disk, be sure to include the drive     
letter of a writable disk  drive if you specify a BROWSE file name.  The      
text editor to produce your own custom command files.                         
                                                                              
                                                                              
4.5.4 CD or CHDIR                                                             
                                                                              
                                                                              
   The CD or CHDIR command is used just as it is at the MS-DOS command level  
to change the current default directory.                                      
                                                                              
   The  argument  of the CD command is the  path  name specification of the   
new default directory.  For example, "CD \IMDISP\IMAGES" would make           
\IMDISP\IMAGES the current directory if it exists.  To change the current     
default drive use the "SYSTEM" command ("SYSTEM L:"  for example) or the      
"FILE" command.  If there is not enough memory available for the system       
command to be executed an error message is displayed.                         
                                                                              
                                                                              
4.5.5 COPY                                                                    
                                                                              
The COPY command will attempt to copy the image last displayed with the       
DISPLAY command, the screen or another buffer to a destination buffer.        
IMDISP will attempt to put the buffer into extended memory.  An FILE option   
is provided to allow the buffer to be put into a file on the disk.            
                                                                              
        COPY  buffer [FILe]                                                   
        COPY  TO buffer [FILe]                                                
        COPY  source TO buffer [FILe]                                         
                                                                              
      where buffer = A-Z                                                      
      where source = A-Z or SCReen                                            
                                                                              
Examples:                                                                     
                                                                              
COPY A                Copies the last displayed image to buffer A             
COPY A TO B           Copies buffer A to buffer B                             
COPY A TO B FILE      Copies buffer A to buffer B, buffer B is a file         
COPY SCREEN TO Z      Copies the entire screen to buffer Z                    
                                                                              
                                                                              
4.5.6 CURSOR                                                                  
                                                                              
                                                                              
   The CURSOR command is used to select a point in a displayed image for      
subsequent display commands.  When first invoked, it places a small cursor    
symbol at the center of the screen.  Depending on the current contents of     
the screen, the cursor may be hard to see.  Moving it with the arrow keys     
on the numeric keypad will help you locate it.  If you have a mouse, it       
will also move the cursor around.                                             
                                                                              
   Whenever the cursor is moved, the current line and sample location of      
the cursor and the DN value of the pixel at that point is printed in the      
lower right portion of the screen.  The cursor will move 16 pixels in the     
selected direction unless the movement value is adjusted using the + or       
keys.                                                                         
                                                                              
                          Numeric Keypad Keys                                 
                    -------------------------------                           
                    |  7   |  8   |  9    | PrtSc |                           
                    | Home | Up   | PgUp  |       |                           
                    -------------------------------                           
                    |  4   |  5   |  6    |  -    |                           
                    | Left |      | Right |       |                           
                    -------------------------------                           
                    |  1   |  2   |  3    |  +    |                           
                    | End  | Down | PgDn  |       |                           
                    -------------------------------                           
                                                                              
                         Action of Keypad Keys:                               
                                                                              
                  7 = Move up and left.                                       
                  8 = Move up.                                                
                  9 = Move up and right.                                      
                  4 = Move left.                                              
                  5 = Not active.                                             
                  6 = Move right.                                             
                  1 = Move down and left.                                     
                  2 = Move down.                                              
                  3 = Move down and right.                                    
                  - = Decrement cursor movement value.                        
                  + = Increment cursor movement value.                        
                                                                              
                                                                              
                     Table 4-2: IMDISP Cursor Keys                            
                                                                              
   Cursor mode is exited by typing a "." (period) or carriage return or by    
tapping the left button on the mouse.  The cursor position is retained for    
future use in DISPLAY commands which use the CENTER option.  It is very       
useful with large images where the entire image may be displayed using the    
subsample option, then a point selected for subsequent display at full        
resolution.                                                                   
                                                                              
   You can specify the starting position of the cursor with the subcommands   
DSL (Display Starting Line) and DSS (Display Starting Sample).  Otherwise,    
the cursor starts off at the position where it was left last.                 
                                                                              
   Example: Type "FILE MONTAGE.IMG" followed by "DISP" to display the         
MONTAGE.IMG file.  Type "CUR" to enter the cursor mode, then move the         
cursor to the center of the Uranus image in the upper left corner of the      
image using the up and left arrow keys.  Now type "." to exit cursor mode,    
then type "DISP ZOOM 4 CENTER" which will display Uranus as a large grainy    
ball on the screen.                                                           
                                                                              
                                                                              
4.5.7 DARKEN                                                                  
                                                                              
   The DARKEN command subtracts a constant value from all pixels in the       
displayed image.  If no value is specified, the default is 10% of the total   
range of DN values (i.e., 2 will be subtracted from all pixels in 16-color    
modes, 26 will be subtracted in 256 color modes).                             
                                                                              
   Examples:                                                                  
                                                                              
   DARKEN                                                                     
   DAR 100                                                                    
                                                                              
                                                                              
4.5.8 DIR                                                                     
                                                                              
                                                                              
   The DIR command is used just as the MS-DOS dir command.  Its argument is   
passed to MS-DOS for execution.  At the end of the directory listing the      
screen will display "Type carriage return to continue:" which will return     
to the IMDISP command mode.  If there is not enough memory available for      
the system command to be executed an error message is displayed.              
                                                                              
                                                                              
4.5.9 DISPLAY                                                                 
                                                                              
                                                                              
   The DISPLAY command reads an image file and displays it on the the         
screen.  If the image is larger than the display screen, the default mode     
is to display as much of the upper left portion of the image as will fit on   
the screen.  The SUBSAMPLE keyword can be used to select every 'n' lines      
and samples so that representations of very large images may be displayed.    
The ZOOM keyword can be used to enlarge a portion of an image on the          
display screen.  Keywords can be specified to begin displaying at any line    
and sample in the image with the SL (starting line) and SS (starting          
sample).  If only a limited number of lines and samples are to be displayed   
the NL (number of lines) and NS (number of samples) keywords can be used.     
The UP, DOWN, LEFT and RIGHT keywords can be used to display different        
portions of the image, relative to the currently displayed portion.  The      
display can also placed at any point on the screen using the DSL (display     
starting line) and DSS (display starting sample) keywords.  The FLIP          
keyword displays the image from the bottom of the screen to the top, rather   
than the other way around.                                                    
                                                                              
   DISPLAY takes the following keywords :                                     
                                                                              
   buffer       displays the image in the named memory buffer                 
                                                                              
   SUBsample n  a positive integral subsampling factor for displaying         
                images larger than the size of the screen.  SUB=2 would       
                display an image at half the resolution.                      
                                                                              
   If the image lines and samples look like this:                             
                                                                              
                 sample values                                                
                                                                              
        line 1      1 2 3 4 5                                                 
        line 2      6 7 8 9 10                                                
        line 3      11 12 13 14 15                                            
                                                                              
   Then the command DISP SUB 2 would produce:                                 
                                                                              
                 sample values                                                
                                                                              
        line 1      1 3 5                                                     
        line 2      11 13 15                                                  
                                                                              
   ZOOM n       a positive integral zoom factor for looking at part of an     
                image close up.  The zoom command replicates pixels by the    
                integer value specified.  If the image lines and samples      
                look like this:                                               
                                                                              
                 sample values                                                
                                                                              
        line 1      1 2 3                                                     
        line 2      4 5 6                                                     
        line 3      7 8 9                                                     
                                                                              
   Then the command ZOOM 2 would produce the following:                       
                                                                              
                 sample values                                                
                                                                              
        line 1      1 1 2 2 3 3                                               
        line 2      1 1 2 2 3 3                                               
        line 3      4 4 5 5 6 6                                               
        line 4      4 4 5 5 6 6                                               
        line 5      7 7 8 8 9 9                                               
        line 6      7 7 8 8 9 9                                               
                                                                              
                                                                              
   CENTER       center the display around current cursor position.   This     
                command is very useful when displaying large images or when   
                zooming in on selected areas.  Should be used after using     
                the CURSOR command.                                           
                                                                              
   NL n                                                                       
   NS n         number of lines or samples from the image file to display     
                                                                              
   SL n                                                                       
   SS n         starting line or sample within the image file to display      
                                                                              
   UP n                                                                       
   DOWN n       adjusts the starting line up or down from the previous        
                value, thereby moving  the display window up or down in the   
                image. The default amount to move up or down is the size of   
                the display.                                                  
                                                                              
   LEFT n                                                                     
   RIGHT n      adjusts the starting sample left or right from the previous   
                value, thereby moving the display window left or right in     
                the image                                                     
                                                                              
   DSL n                                                                      
   DSS n        start the image display at the specified line and sample on   
                the display screen.                                           
                                                                              
   FLIP         flips the image top to bottom, so the image is displayed      
                from the bottom of the screen to the top.                     
                                                                              
   NOPrompt     displays the image without display the command line prompt    
                (COMMAND:) at the bottom of the screen.  This is to           
                accommodate screen captures of IMDISP displays.               
                                                                              
   AUToset n    sets DNLO and DNHI to n% of the full range, based on the      
                histogram.  The default is 5%.                                
                                                                              
   NOMemory     tells IMDISP not to attempt to load the image into extended   
                memory as it displays the image.                              
                                                                              
   SOUrce       used to display the source file of a browse image.  The       
                source file is specified with the SOURCE_FILE_NAME and        
                SAMPLING_FACTOR keywords in the label.  The source file is    
                centered on the current cursor position in the browse file.   
                Does not work with Voyager or Viking compressed images.       
                                                                              
   Examples: The user wants to display an entire Voyager image (800 x 800)    
on the display screen then display a portion of the image at full             
resolution.  Type "FILE MIRANDA1.LBL", then "DISP SUB 2" to display the       
entire image at half resolution, Use the CURSOR command to move the cursor    
to the center of an area of interest.  Exit the cursor mode by typing ".",    
then type "DISP CENT" to display the selected portion of the image at full    
resolution.                                                                   
                                                                              
   The user wishes to place 2 images which are each 800 lines by 800          
samples on the screen next to each other.  The first file is opened with      
"FILE IMAGE1.IMG".  The "DISPLAY SUB 4" command is given to display every     
4th line and sample of the image to create a 200 x 200 display. Next the      
"FILE IMAGE2.IMG" command is given.  Now a "DISPLAY SUB 4 DSS 201" is given   
to place the second image on the screen starting at display sample position   
201, next to the first image.                                                 
                                                                              
                                                                              
    Examples:                                                                 
                                                                              
    DISP SUB 2                                                                
    DISP SUB 3 DSS 200                                                        
    DISP SUB 4 DSL 300                                                        
    DISP CEN ZOOM 2              (Use CUR first to select a center)           
    DISP A                   Displays buffer A                                
    DISP A SUB 2             Displays buffer A, subsampled twice              
    DISP A CEN ZOOM 3        Zooms in on the center of buffer A               
                                                                              
                                                                              
4.5.10 ENHANCE                                                                
                                                                              
                                                                              
   The command ENHANCE applies a number of image processing filters to the    
image.  It can either be applied to the entire image (from the input file)    
or simply to the displayed portion of the image.                              
                                                                              
   ENHANCE takes the following subcommands:                                   
                                                                              
     SCReen         applies the filter to the entire screen.  If this         
                    option is not selected, then the filter will be applied   
                    to the image last displayed with the DISPLAY command.     
                                                                              
     BAAlke         applies an enhancement filter developed by Ron Baalke.    
                                                                              
     CONvolution n  applies a convolution filter to the image which has the   
                    effect of detecting the edges.  A 3x3 mask is used.       
                    There are two variations of this filter used (n = 0 or    
                    1). Integer arithmetic is used to speed up the process.   
                    The following weighted mask is used:                      
                                                                              
                               -1  -1  -1                                     
                               -1   8  -1                                     
                               -1  -1  -1                                     
                                                                              
     EDGe n         applies an edge enhancement filter to the image using a   
                    3x3 mask.  There are four variations of this filter (n    
                    = 0, 1, 2, 3). Integer arithmetic is used to speed up     
                    the process.                                              
                                                                              
     LOG  n         applies a logarithmic filter to the image which has the   
                    effect of enhancing the contrast in the image. Useful     
                    on dark images or on images like stars and galaxies.      
                    The parameter that goes with this one is a little         
                    different than the other filters, in that you specify a   
                    factor (default=40) which is multiplied with the log of   
                    the pixel value. Examples:                                
                                                                              
     MEAn n         applies a mean filter to the image which has the effect   
                    of smoothing out the image.  There are three variations   
                    of this filter (n = 0, 1).  A 3x3 (n=0), 5x5 (n=1) or     
                    7x7 (n=2) mask is used where the middle pixel is          
                    replaced by the average of the nine pixels in the mask.   
                    Integer arithmetic is used to speed up the process.       
                                                                              
     MEDian         applies a median filter to the image which has the        
                    effect of smoothing out the image.  A 3x3 mask is used    
                    where the middle pixel is replaced by the middle of the   
                    nine pixels after they have been sorted. The sort used    
                    is a simple bubble sort which is terminated halfway       
                    through the sort process since the median value will be   
                    found by then.                                            
                                                                              
     POWer n        modifies the pixels of the image by the following         
                    equation:                                                 
                                                                              
                       newDN = numDN * (oldDN/numDN) ^ n                      
                                                                              
                    where n is a floating point number.  The default value    
                    is 2.0.  Values less than 1.0 tend to brighten the        
                    image, while values greater than 1.0 tend to darken it.   
                                                                              
     STAir n        groups pixels together with the net result of smoothing   
                    the image.  The default step increment is 8               
                                                                              
     SMEar          applies a filter which averages the image in the          
                    vertical direction.  The result is to "smear" the         
                    images down the screen.                                   
                                                                              
     UNSharp        applies an unsharp mask to the image, which has the       
                    effect of enhancing edges in the image. It is the         
                    equivalent of performing a merge with 3 times the         
                    original image minus 2 times the image after it has       
                    been blurred with a 5x5 mean filter.                      
                                                                              
                                                                              
     Examples:                                                                
                                                                              
        ENH MEAN                                                              
        ENH EDGE                                                              
        ENHANCE EDGE 2                                                        
        ENHANCE BAALKE SCREEN                                                 
        ENH CON 1                                                             
        ENH SMEAR SCR                                                         
        ENH POWER .1   (similar to ENH LOG)                                   
        ENH STAIR 2    (creates a binary 2-color image)                       
                                                                              
                                                                              
4.5.11 ERASE                                                                  
                                                                              
                                                                              
   The command ERASE causes the screen to be erased by setting all of the     
pixels to 0, which may not necessarily be black depending on the palette      
setting.  If the REFRESH option is selected, then only the refresh buffer     
will be erased.  Memory buffers (denoted by letters A through Z) can also     
be erased.                                                                    
                                                                              
    Examples:                                                                 
                                                                              
       ERA            erases the screen                                       
       ERA REFRESH    erases the refresh buffer                               
       ERA A          erases the memory buffer named A                        
                                                                              
                                                                              
4.5.12 EXIT                                                                   
                                                                              
                                                                              
   The EXIT command exits IMDISP and returns the user to the MS-DOS           
operating system.  The contents of the image display and refresh buffer are   
discarded.   The single subcommand NOClear will leave the computer display    
in graphics mode, and will not clear the screen.  Same as QUIT.               
                                                                              
                                                                              
4.5.13 FILE                                                                   
                                                                              
                                                                              
   FILE takes just a value which is the file name. The specified file will    
be opened, or an error message issued if the file cannot be opened.  The      
capability to directly address any sector on the CD-ROM disk by providing     
its physical address (minute, second and sector number) is also available     
to users of the Microsoft Extensions software.  There is one keyword,         
NOMEMORY.  If not given, the FILE command will attempt to put the image       
directly into extended memory (where the DISPLAY command will find it).  If   
specified, or if the image doesn't fit into extended memory, the DISPLAY      
command will read the image from disk.  FILE can now display GIF-format       
images, as well.  It does this automatically if the filename extension is     
.GIF.                                                                         
                                                                              
   If the FILE command is specified without a filename, or with a filename    
mask which contains a wildcard, the program will display a list of file       
names in the current directory.  Each file name is preceded by a number.      
Typing the number associated with a file name will select that file for       
processing.  File names that actually represent lower level directories are   
indicated with a <d> symbol after the name, Directories can be traversed      
downward by selecting the number associated with a directory name.  Upward    
traversal is by selecting the item identified as PARENT DIR.  This will       
move upward in the directory hierarchy.                                       
                                                                              
   The prompt mode clears the screen and displays a menu of files (matching   
the wildcard mask, if one was used) and commands.  These commands allows      
specification of the default drive, a file "mask" to use in selecting file    
names for display and options for moving through the list of files when the   
current directory contain more than 30 files. The top line of the display     
also indicates how many files are in the current directory.  After exiting    
the FILE prompt mode, the previous contents of the display screen can be      
recovered by typing "REFRESH".                                                
                                                                              
   The FILE prompt mode subcommands:                                          
                                                                              
     D    select default disk drive                                           
     M    specify a file selection mask to use in displaying files on the     
          screen.                                                             
     N    display the next set of file names on the screen if there are       
          more files in the current directory than can be displayed on one    
          screen.                                                             
     P    display the previous set of file names.                             
     Q    quit the file selection mode and return to IMDISP command mode.     
                                                                              
   The N, P and Q commands are executed immediately.  If the D or M           
commands are selected, the user is prompted to enter a drive letter or file   
mask.                                                                         
                                                                              
   If the file selected by the "FILE filename" or FILE prompt mode has a      
valid label, either PDS or VICAR2, then the number of lines and samples and   
the pixel size will be displayed.  If the file is unlabeled then the          
program will prompt for the values to use for the number of lines and         
samples, the number of bits per pixel, and the number of header bytes. PDS    
detached labeled images can also be displayed.  The specified file remains    
the current file until a new FILE command is given.  The FILE command         
resets the SET DNLO and SET DNHI values to the minimum and maximum for the    
pixel size (normally 0 and 255).  If a specified filename is not found in     
the current directory then an error message is displayed.                     
                                                                              
   If the unlabeled image has a regular format, that is a uniform structure   
of repeating lines and samples, the user can specify this information when    
prompted by the program.  For example, an image named ASTERIA.DAT with one    
1422 byte header block followed by an image composed of 370 lines by 450      
samples of 8 bit pixels would be processed as follows:                        
                                                                              
   At the COMMAND: prompt type "FILE ASTERIA.DAT".  The program will          
display the message:                                                          
                                                                              
  Input file does not have a proper label.                                    
  Input number of lines: 370           enter the value 370                    
  Input number of samples: 450         enter the value 450                    
  Input size of each sample: 8         enter the value 8                      
  Input size of header label: 1422     enter 1422 for the size of the         
                                       foreign label block).                  
                                                                              
   The physical address of a data block on the CD-ROM can also be specified   
using the syntax 'FILE "CD:mm:ss:bb"', where mm is the minute, ss the         
second, and bb the sector block number of the beginning of the desired data   
area.  The CD:mm:ss:nn must be in double quotes and the CD must be            
capitalized! This mechanism can be used to access files on non-High Sierra    
format disks.  This will only work on systems using the Microsoft             
Extensions software.                                                          
                                                                              
                                                                              
4.5.14 HELP                                                                   
                                                                              
                                                                              
   HELP displays the online help message.  If followed by the name of a       
valid command the message for that command is displayed.  HELP is not         
provided for MS-DOS commands (DIR, CHDIR, CD and TYPE).                       
                                                                              
                                                                              
4.5.15 HISTOGRAM                                                              
                                                                              
                                                                              
   The HISTOGRAM command produces a plot showing the number of pixel values   
in the image at each DN level.  The range of DN values is displayed on the    
x-axis and the number of occurrences of a specific DN value on the y-axis     
(See Figure 4-1).                                                             
                                                                              
   The HISTOGRAM command reads through the image, calculates the histogram,   
and then displays the plot on the screen.  The histogram is scaled so that    
the third highest histogram value is used as the maximum. It is recommended   
that the SUBSAMPLE or other subsetting keywords be used to speed up           
histogram calculation, which can be quite slow for large images and for       
images stored on CD-ROM.  Histogram plots are displayed on top of any image   
currently displayed on the screen, so the user may wish to use the ERASE      
command to clear the screen prior to using HISTO.  After the histogram is     
displayed, the image can be restored using the REFRESH command.               
                                                                              
                                                                              
            27582 |      .                                                    
                  |      ..                                                   
                  |     ....                                                  
           COUNT  |     .....                                                 
                  |    .......                                                
                  |    .........                                              
                  |   ............                                            
                  |  ...............                                          
                   --+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                          
                   0   64   128   192   256                                   
                            DN value                                          
                                                                              
                   Figure 4-1: Sample Image Histogram                         
                                                                              
                                                                              
   By evaluating the histogram, the user can determine the optimum settings   
for the SET (DNLO and DNHI) command to produce a useful display.  In the      
example above, the image data are clustered between DN values 32 and 144.     
Using the default settings of the EGA display mode the colors assigned to     
the 2 lowest color values and the 7 highest values (representing DN values    
from 0 to 31 and from 144 to 255) would not be used since the image           
contains no pixels with these values.                                         
                                                                              
   By using the "SET DNLO 32 DNHI 144" command the 16 display levels          
available on the EGA display would be assigned to values between 32 and 144   
rather than distributed evenly from 0 to 255, and all 16 colors would be      
used in the display.                                                          
                                                                              
   HISTOGRAM takes the following keywords and arguments:                      
                                                                              
    SUBsample n  a integral subsample factor.  For speeding up HISTOGRAM,     
                 use of "SUBSAMPLE 4" is recommended                          
                                                                              
    buffer       displays the histogram of the image in the named memory      
                 buffer                                                       
                                                                              
    NL n                                                                      
    NS n         number of lines and samples from image                       
                                                                              
    SL n                                                                      
    SS n         starting line and sample in image                            
                                                                              
    CENT         perform the histogram on only the displayed portion of the   
                 image.                                                       
                                                                              
   Two special keywords can be used with Voyager or Viking images on the      
PDS CD-ROM disks.  These will extract histogram values stored with the        
image on the CD-ROM disk and reduce the time required for the histogram to    
be generated from more than 1 minute to about 3 seconds.  Note that these     
commands will not work with Voyager image files in the                        
\PLANET\JUPITER\ATMOS directory, or with versions of system software          
written before April 1987.                                                    
                                                                              
    VOY   use histogram from Voyager CD-ROM engineering data                  
    VIK   use histogram from Viking CD-ROM engineering data                   
                                                                              
                                                                              
4.5.16 LABEL                                                                  
                                                                              
                                                                              
   The LABEL command prints the labels for the currently selected image       
file on the screen.   It pauses after each screen full of data, and waits     
for you to press a key before displaying the next screen of data. You can     
terminate the listing by pressing the letter 'Q' to quit and return to        
IMDISP.                                                                       
                                                                              
                                                                              
4.5.17 LOG                                                                    
                                                                              
                                                                              
   The LOG command controls logging commands to a text file as they're        
entered.  The resulting file can be used as a batch file, to repeat the       
command sequence, or as a record of what operations have been performed.      
The file is automatically flushed and closed when you exit IMDISP.            
                                                                              
   The LOG command takes the following keywords and arguments:                
                                                                              
    ON             opens a log file called IMDISP.LOG.  Commands will be      
                   copied into this file until it is either closed or you     
                   exit IMDISP.                                               
                                                                              
    FILe  fname    opens a log file called fname (defaults to IMDISP.LOG).    
                                                                              
    CLOse                                                                     
    OFF            closes the current log file.                               
                                                                              
4.5.18 MASK                                                                   
                                                                              
   The MASK command is used to mask out pixels on the low or high end of      
the color palette.  It is particularly userful when merging images            
together.  It sets all the pixels with a DN value above or below a            
specified value to a default.                                                 
                                                                              
   The MASK command takes the following keywords and arguments:               
                                                                              
    LO n           sets all pixels with a DN value of n or less to the        
                   default DN value of 0.                                     
                                                                              
    HI n           sets all pixels with a DN value of n or greater to the     
                   default DN value of 255.                                   
                                                                              
    WITH n         overrides the default values for LO and HI, and sets the   
                   pixels to the DN value n.                                  
                                                                              
Examples:                                                                     
                                                                              
MASK LO 20             Sets the DN values for all pixels with DN values of    
                       20 or less to 0.                                       
                                                                              
MASK LO 20 WITH 255    Sets the DN values for all pixels with DN values of    
                       20 or less to 255.                                     
                                                                              
MASK HI 200            Sets the DN values for all pixels with DN values of    
                       200 or more to 255.                                    
                                                                              
MASK HI 200 WITH 0     Sets the DN values for all pixels with DN values of    
                       200 or more to 0.                                      
                                                                              
                                                                              
4.5.19 MENU                                                                   
                                                                              
                                                                              
   The MENU command reads a file containing a list of file names and places   
the user in the MENU mode, where files from this list can be selected for     
display.  The MENU mode is similar to the FILE mode, except that the list     
of files presented is that provided in the menu file, rather than from a      
selected directory.                                                           
                                                                              
   The MENU mode can be invoked by typing "MENU filename.MNU" at the          
COMMAND: prompt.  It can also be invoked on program startup by typing         
"IMDISP filename.MNU" to initiate the program.  The menu file must use the    
".MNU" extension to startup IMDISP in MENU mode.                              
                                                                              
   Subcommands of the MENU mode are as follows:                               
                                                                              
   #         - Enter the number corresponding to a desired                    
               file name to select the file.                                  
                                                                              
   P)revious - display the previous screen of file names                      
   N)ext     - display the next screen of file names                          
   Q)uit     - quit or exit from MENU mode                                    
                                                                              
   After selecting and displaying an image, the user can return to the        
current menu by typing "MENU" at the COMMAND: prompt.                         
                                                                              
   A menu file can take either of two formats.   The preferred format is a    
PDS labelled table file containing file names.  A sample file is shown        
below:                                                                        
                                                                              
NJPL1I00PDS100000000      = SFDU_LABEL                                        
FILE_TYPE                 = TABLE                                             
RECORD_FORMAT             = STREAM                                            
OBJECT                    = FILE_NAME                                         
 TYPE                     = LITERAL                                           
 LENGTH                   = 80                                                
ENDOBJECT                                                                     
NOTE                      = "Sample MENU file for IMDISP"                     
END                                                                           
L:\OCEAN\SCBMEAN.IMG                                                          
L:\OCEAN\WCMEAN.IMG                                                           
L:\PLDS\TMCH01.DAT                                                            
L:\PLDS\DEM.DAT                                                               
L:\PLANET\SATURN\ATMOS\C3497355.IMG                                           
<END OF FILE>                                                                 
                                                                              
   A second abbreviated form may also be used, where only the filenames are   
specified in the ".MNU" file.  In this case the file would only contain the   
filenames shown after the END statement in the example above.                 
                                                                              
                                                                              
4.5.20 MERGE                                                                  
                                                                              
                                                                              
The MERGE command will merge buffers, images or the screen together.  A       
scaling option can be provided to control the amount of merging.  If the      
TO option is not used then the result will be displayed on the screen by      
default.  The result can also be written to a buffer.                         
                                                                              
        MERGE buffer                                                          
        MERGE source1 [scale1] WITH source2 [scale2] [TO buffer] [FILE]       
                                                                              
Examples:                                                                     
                                                                              
MERGE A                   Merge the last displayed image with buffer A and    
                          display the result back on the screen               
                                                                              
MERGE A WITH B            Merge buffer A with buffer B and display the result 
                          on the screen.  Since no scaling parameter are      
                          specified IMDISP will default to 50% of A and 50% of
                          B.                                                  
                                                                              
MERGE A WITH B TO C       Merge buffer A with buffer B and store the result   
                          into buffer C                                       
                                                                              
MERGE A WITH B -1         Subtract buffer A from buffer B                     
                                                                              
MERGE A .75               Merge 25% of the last displayed image with 75% of   
                          buffer A, display the result on the screen.         
                                                                              
MERGE A .75 with B .8     Merge 75% of buffer B with 80% of buffer B, display 
                          result on the screen                                
                                                                              
MERGE B WITH SCREEN       Merge buffer B with the screen                      
                                                                              
MERGE A 3 WITH B -2 TO C FILE    Subtract 200% of buffer B from 300% of A,    
                                 store the result in buffer.                  
                                                                              
                                                                              
4.5.21 OVERLAY                                                                
                                                                              
                                                                              
   The OVERLAY command draws a lat/lon overlay grid on the displayed image.   
It is intended only for use with the Ocean Data System, West Coast Time       
Series CD-ROM in this program version.                                        
                                                                              
   The OVERLAY command has the following arguments:                           
                                                                              
   MAXLAT   Latitude of top of image.                                         
   MINLAT   Latitude of bottom of image.                                      
   MAXLON   Longitude of left side of image.                                  
   MINLON   Longitude of right side of image.                                 
                                                                              
   LEGend   Draw a color scale with the overlay.                              
                                                                              
                                                                              
4.5.22 PALETTE                                                                
                                                                              
                                                                              
   The PALETTE command is used for changing the colors assigned to            
displayable color values.  This is done by modifying an internal color        
table which assigns intensity values for red, green and blue to a color       
value, The EGA provides 4 intensity values for each of 3 colors, so that 64   
different colors can be created.  However, the EGA pixels are only 4-bits     
each so only 16 color values can be used simultaneously.                      
                                                                              
   The palette can be modified using the EDIT command and saved and loaded    
from a disk file.  The edit mode is invoked by typing PALETTE EDIT.  With     
the EGA display, a bar containing 16 colors or shades will be displayed on    
the bottom of the screen.  A small square will appear in the middle of the    
center color box.  This indicates that this color value is currently          
selected for editing.  To select another color value for editing, move the    
small square to the appropriate color using either the "4" (left arrow) and   
"6" (right arrow) keys on the numeric keypad or the mouse.  The "7" (Home)    
and "1" (End) keys move to the beginning and end of the palette. Pressing     
the "Ctrl" key with either the "4" or "6" keys will jump the small square     
left or right by 8 color bars.                                                
                                                                              
   The color of the current color box is changed with the "R", "G", and "B"   
keys (for red, green, and blue).  Upper case letters increase the amount of   
the primary color, and lower case keys decrease the amount of the color.      
The "8" (up arrow) and "2" (down arrow) keys increase and decrease,           
respectively, the amount of red, green, and blue simultaneously.  The left    
button on the mouse does the same thing.  Other commands in the palette       
edit mode are the "S" and "s" commands, which will shift all colors one       
value to the right or left, and the "x" command, which will exchange color    
values (the color setting for color 0 becomes the setting for color 15,       
while 15 replaces 0, the color setting for color 1 becomes the setting for    
14, while 14 replaces 1, etc.).  The up and down arrow keys can also be       
used to cycle through the colors available in a given display mode one at a   
time. Type the "." key or carriage return to exit the edit mode.              
                                                                              
   PALETTE takes the following keywords and arguments:                        
                                                                              
    EDIT n         to interactively adjust an n-color palette.  See edit      
                   description (above) for details                            
                                                                              
    PSEUDOCOLOR n  PS = 0 for default EGA palette,                            
                   PS = 1 for gray scale palette,                             
                   PS = 2 or 3 for pseudo color palettes (16 levels)          
                   PS = 4, ..., 9 for pseudo color palettes (256 levels)      
                                                                              
    SAVE filename  saves the specified palette on disk                        
    LOAD filename  loads the specified palette from disk, if no filename is   
                   specified, then list of files is displayed.  See FIL       
                   command for more details.                                  
    DIS            displays the current palette on the screen                 
    ERA            erases the current palette from the screen                 
    CYC  n         cycles the color palette                                   
                                                                              
                   CYC = 0  "blinks" the palette                              
                   CYC = 1  blinks four times                                 
                   CYC = 2  rotates the palette for spectacular results       
                   CYC = 3  rotates and feeds in random colors                
                   CYC = 4  randomizes the palette                            
                   CYC = 5  double rotates the palette                        
                   CYC = 6  random swaps of the palette                       
                                                                              
                   Any key will stop the palette cycling.  A 'S' or 's' key   
                   will save the palette which is currently being             
                   displayed, any other key will restore the palette to its   
                   original colors.                                           
                                                                              
                   CYCLE itself has two keywords.                             
                                                                              
                   FASt     sets the delay between changes to .1 second       
                            (the default is .3).  Works best on machines      
                            with fast video, where flicker is minimized.      
                                                                              
                   TIMe n   runs the PAL CYCLE command for n seconds          
                            (useful in batch files).                          
                                                                              
                                                                              
   The default palette file for LOAD or SAVE operations is IMDISP.PAL. The    
format of the default color palette when stored in a palette file is as       
shown below:                                                                  
                                                                              
NJPL1I00PDS000000784     = PDS_SFDU_LABEL                                     
FILE_TYPE                = TABLE                                              
RECORD_TYPE              = STREAM                                             
FILE_RECORDS             = 28                                                 
TABLE_ROWS               = 16                                                 
ROW_COLUMNS              =  4                                                 
COLUMN_NAME              = (COLOR_NUMBER,                                     
                            GREEN_VALUE,                                      
                            BLUE_VALUE)                                       
COLUMN_TYPE              = (INTEGER,INTEGER,INTEGER,INTEGER)                  
END                                                                           
  0   0   0   0                                                               
  1  64   0   0                                                               
  2 128   0   0                                                               
  3 192   0   0                                                               
  4 192  64   0                                                               
  5 192 128   0                                                               
  6 192 192   0                                                               
  7 128 192   0                                                               
  8   0 192   0                                                               
  9   0 192 128                                                               
 10   0 128 128                                                               
 11   0 128 192                                                               
 12   0   0 192                                                               
 13 128   0 192                                                               
 14 192   0 192                                                               
 15 192 192 192                                                               
                                                                              
   The first column of the palette table is the color value number for the    
display, and columns 2, 3 and 4 represent the intensity of the red, green     
and blue (respectively) primary colors on a scale of 0 to 255. With the EGA   
display these values are: 0 = off; 64 = low; 128 = medium; 192 = high.        
                                                                              
                                                                              
   Examples:                                                                  
                                                                              
      PAL PS 1          (Gray scale palette)                                  
      PAL PS 7          (Built in color palette #7)                           
      PAL DIS                                                                 
      PAL EDI                                                                 
      PAL CYC 2                                                               
      PAL CYC 4                                                               
                                                                              
                                                                              
4.5.23 PERSPECTIVE                                                            
                                                                              
   PERSPECTIVE displays the current image as a pseudo-perspective plot.       
This is useful for inspecting the topography of an image - brighter areas     
will seem to be raised higher than dark areas.                                
                                                                              
   The PERSPECTIVE command has these arguments:                               
                                                                              
   SL  n   displays the plot starting at line n of the image                  
                                                                              
   SCR     reads the image from the screen, rather than from disk (slightly   
           faster).                                                           
                                                                              
                                                                              
4.5.24 PROFILE                                                                
                                                                              
                                                                              
   PROFILE plots the DN values of pixels located along a line between two     
points in the image, i.e., it creates a graph of DN value versus pixel        
along the line joining the two points, CURsor mode is used to select the      
two endpoints; typing "." or carriage return, or tapping the left mouse       
button, selects the current cursor position as the endpoint.  After the       
endpoints are selected a line is drawn between the points and the graph is    
plotted at the bottom of the screen, showing the DN values on the x-axis      
and the positions along the line on the y-axis.                               
                                                                              
                                                                              
4.5.25 QUIT                                                                   
                                                                              
                                                                              
   The QUIT command exits IMDISP and returns the user to the MS-DOS           
operating system.  The contents of the image display and refresh buffer are   
discarded.   The single subcommand NOClear will leave the computer display    
in graphics mode, and will not clear the screen.                              
                                                                              
                                                                              
4.5.26 REFRESH                                                                
                                                                              
                                                                              
   REFRESH redisplays the image plane from the refresh buffer.  When images   
are written to the screen they are also written to the refresh buffer.  The   
REFRESH command writes this buffer back to the screen, thereby erasing any    
graphics or text overlaying the image on the screen. The refresh buffer       
contains as many lines from the display screen as there is room for in        
memory.  REFRESH takes no parameters.  It can also be used after the FILE     
prompt mode to redisplay the contents of the refresh buffer.  By default,     
the refresh buffer is allocated from extended (XMS) memory.  If extended      
memory is present, the refresh buffer is on by default.  If there isn't any   
extended memory, or not enough extended memory is available, the refresh      
buffer is off by default, by may be turned on to use a virtual file.  The     
location of the virtual file is given by the environment variable             
IMREFRESH.                                                                    
                                                                              
   REFRESH is commonly used after the HELP command, or after a HISTOGRAM or   
PROFILE command to remove text and plots from the display screen.             
                                                                              
   The refresh buffer can be disabled/enabled with the SET command:           
                                                                              
      SET REFRESH ON                                                          
      SET REFRESH OFF                                                         
                                                                              
                                                                              
4.5.27 SAVE                                                                   
                                                                              
                                                                              
   The SAVE command copies the contents of the display screen to a file. On   
EGA systems the display buffer contains only 4-bits per pixel, so             
specifying BP = 8 will write the 4-bit pixels in full bytes, but does not     
save full 8-bit pixels even if the input image is an 8-bit image. Use the     
COPIM utility program to produce a full resolution subset of an 8-bit image   
in that case.  An 8-bit display device can save an image with full 8-bit      
pixels.                                                                       
                                                                              
   SAVE takes the following arguments and keywords, where the filename must   
immediately follow the SAVE command:                                          
                                                                              
    filename    filename of image to save - if the extension on the           
                filename is .GIF, the file will be saved in GIF format        
                instead of PDS format.                                        
                                                                              
    NL n                                                                      
    NS n        number of lines and samples to save                           
                                                                              
    SL n                                                                      
    SS n        starting line and sample to save                              
    BP n        number of bits per pixel in output image                      
    REFRESH     save the displayed image into the refresh buffer              
                                                                              
   Example: Save a 200 line by 200 sample area at the center of an image in   
the file SMALL.IMG.  First use the FILE command to select and display an      
input image.  Now type:                                                       
                                                                              
   "SAVE SMALL.IMG SL 100 SS 210 NL 200 NS 200"                               
                                                                              
to save the portion of the image beginning at line 100 and sample 210 in      
the new file SMALL.IMG.                                                       
                                                                              
                                                                              
4.5.28 SET                                                                    
                                                                              
                                                                              
   SET is used set various display options.  It may be used to display and    
change the DN (pixel value) range that is used to compress the pixel values   
to the range appropriate for the display device.  The default, which is       
reset for each new file, is the full range of DN values for the particular    
pixel format (e.g.  0 to 255 for byte).                                       
                                                                              
   The results of a SET DNLOW or SET DNHIGH command will not take effect      
until the next DISPLAY command is performed.                                  
                                                                              
   SET can also be used to specify a file name to be used by the browse       
command, change the default display resolution or change the number of        
samples used to display the current image.                                    
                                                                              
   Set takes the following keywords:                                          
                                                                              
    DNLOW n                                                                   
    DNHIGH n  where values less than DNlow are set to color value 0, values   
              greater than DNHIGH are set to the maximum color value          
              available, and the color values between are assigned equally    
              to the DN values between Dnlow and DNhi.                        
                                                                              
    BROwse filename                                                           
              sets a file name to be used for the browse file.   This file    
              name will override  the default file name, which is             
              'c:browse.cmd'.                                                 
                                                                              
    NS n      sets the number of samples to be used for the next DISPLAY      
              command.                                                        
                                                                              
    REFresh ON                                                                
    REFresh OFF                                                               
              toggles the state of the refresh buffer on or off.  If IMDISP   
              detects the presence of extended memory (XMS - managed by a     
              device driver like HIMEM.SYS or QEMM), the refresh buffer       
              will default to ON.  If no XMS is present, the default is       
              off, and turning the refresh buffer on will cause IMDISP to     
              set up a scratch file to be used as the refresh buffer.         
                                                                              
    DELay ON                                                                  
    DELay OFF (default)                                                       
              enables/disables the time delay before executing commands.      
              Most useful when used in batch file, because it allows the      
              commands to play slowly instead of as fast as possible.         
                                                                              
    PROmpt ON  (default)                                                      
    PROmpt OFF                                                                
              enables/disables the display of the command names before        
              execution.  Most useful when used in batch files, because it    
              prevents the command prompts from appearing on the screen.      
                                                                              
    DISPLAY name                                                              
              sets the current display device.   You might use this to        
              change from Super VGA resolution to VGA if you wish to have     
              bigger pixels for displaying images with the BROWSE command,    
              for example.  To do this, you would type the command SET DIS    
              VGA.  The change will take place immediately.   The current     
              values for DISPLAY are                                          
                                                                              
              CGA         (640x200x2)                                         
              EGA         (640x350x16)                                        
              EGA480      (640x480x16)                                        
              VGA320      (320x200x256)                                       
              VGA         (640x480x16)                                        
              ATI640      (640x480x256) - ATI VGA Wonder Board (512K)         
              ATI800      (800x600x256) - ATI VGA Wonder Board (512K)         
              ATI1024     (1024x768x16) - ATI VGA Wonder Board (512K)         
              EVGA512     (512x480x256) - Everex EV-673 Board (256K)          
              EVGA640     (640x400x256) - Everex EV-673 Board (256K)          
              ORCHID      (640x480x256) - Orchid ProDesigner+ Board (512K)    
              ORCHID800   (800x600x256) - Orchid ProDesigner+ Board (512K)    
              ORCHID1024 (1024x768x256) - Orchid ProDesigner+ Board (1MB)     
              PARADISE    (640x480x256) - Paradise SuperVGA Board (512K)      
                          (640x400x256) - Paradise SuperVGA Board (256K)      
              PGA         (640x480x256) - PGA Board                           
              TRIDENT     (640x480x256) - Trident-based SVGA boards (512K)    
              VESA       (1024x768x256) - VESA SVGA Interface (1MB) (test)    
                                                                              
    PALette directory                                                         
              Sets the default palette directory.  This is used with the      
              PAL LOAD command.  If PAL LOAD is used with no parameters,      
              IMDISP will go to the default palette directory and display     
              the files there.                                                
                                                                              
    BUFfers directory                                                         
              Sets the directory to hold the buffers as files instead of      
              memory buffers.  Useful when not enough extended (XMS) memory   
              exists to create the buffers.                                   
                                                                              
   For example, using the default color palette and an EGA display with 16    
color values available, the command "SET DNLO 100 DNHI 164" will assign DN    
values below 100 to black and DN values above 164 to white, and spread the    
16 color values between the DN limits, thus each color value will represent   
4 DNs (value 0 = DN 100 to 103; value 1 - DN 104 to 107, etc.).               
                                                                              
   If values other than the default are used then the images will display     
more slowly because scaling divisions are required.  SET with no parameters   
will display the current values.                                              
                                                                              
   The DNLO and DNHI values are reset to the minimum and maximum for a        
given pixel size when a FILE command is issued.                               
                                                                              
                                                                              
4.5.29 SLANT                                                                  
                                                                              
                                                                              
   SLANT displays the image slanted either to the left or right.  This is     
done by shifting each line of the image by 1 pixel.  It is particularly       
useful for finding errors in image headers.                                   
                                                                              
                                                                              
   Examples:                                                                  
                                                                              
      SLANT                (slants image to the right)                        
      SLANT LEFT                                                              
                                                                              
                                                                              
4.5.30 STRETCH                                                                
                                                                              
                                                                              
   STRETCH sets the palette to a gray scale stretched between the two         
specified pixel values.  Stretch is most useful on the PGA display where 16   
gray levels are available.  On the EGA display the stretch command            
activates the gray level palette which provides only 4 gray levels.  Use      
the PAL PS 0 command to return the display to the default palette after       
performing a stretch.                                                         
                                                                              
   STRETCH takes the following keywords :                                     
                                                                              
    LOW n                                                                     
    HIGh n   the low and high DN values of the stretch.                       
                                                                              
                                                                              
   These pixel values refer to the DN values in the current image display,    
not necessarily in the original image (scaling may have been involved). For   
example with the EGA display the DN values in the display range from 0 to     
15, even if a byte image is being displayed.                                  
                                                                              
   The STRETCH command is not recommended for use on EGA systems.             
                                                                              
                                                                              
4.5.31 SYSTEM                                                                 
                                                                              
                                                                              
   The SYSTEM command is used to send a command to MS-DOS.                    
                                                                              
   For example "SYS L:" will set the L: drive as the current default drive.   
If there is not enough memory available for the system command to be          
executed an error message is displayed.  The SYS command will not work on     
floppy disk systems unless the file "COMMAND.COM" is present on the floppy    
disk with the IMDISP program.                                                 
                                                                              
   The SYSTEM command in this version of IMDISP will attempt to free as       
much of memory as possible, by swapping most of the program to scratch        
space.  It tries to find Extended memory (XMS), Expanded memory (EMS) or      
disk space, in that order.  If it succeeds, only a small amount of IMDISP     
remains in memory, leaving far more memory for DOS functions that previous    
versions.  If the attempt to swap fails, the program will try to swap to      
DOS with the available memory.  Currently, you must have about the same       
amount of free XMS, EMS or disk space as you have memory free before          
running IMDISP (i.e., IMDISP allocates all available memory to itself when    
it starts, and requires that much scratch space when swapping out).           
                                                                              
   The swap process, if it attempts to write out to a scratch disk file,      
will use the directory specified by the environment variable IMBROWSE. If     
IMBROWSE doesn't exist, IMDISP will write the scratch file to the root        
directory of drive C:.  The scratch file is deleted when you return to        
IMDISP (using the EXIT command at the DOS prompt).                            
                                                                              
                                                                              
4.5.32 TEXT                                                                   
                                                                              
                                                                              
   The text command can be used to display a string of text on the screen.    
The text string can be entered on the command line, enclosed in               
apostrophes or quotes (e.g., TEXT `This is a text string').  If the text      
string is not entered on the command line the program will prompt for the     
string to be displayed.                                                       
                                                                              
   Once the command is issued and the text string entered the program is      
placed in CURSOR mode so that the display position can be selected. This is   
done by using the arrow keys to move the cursor to the desired location.      
After the position is selected, the user types a period (.) or carriage       
return and the text will be written on the display screen.                    
                                                                              
   The TEXT command has one argument and two optional keywords.               
                                                                              
   LINe      The line number to position the text at.                         
   SAMple    The sample number to position the text at.                       
   NOPrompt  Will display text without the command line prompt.               
                                                                              
   'text...' The text string to be printed, enclosed in quotes or             
             apostrophes.                                                     
                                                                              
   The text command writes over image data in the display and refresh         
buffer, thus the underlying portion of the image is lost.                     
                                                                              
                                                                              
4.5.33 TYPE                                                                   
                                                                              
                                                                              
   The TYPE command is used to type the contents of a text file on the        
display screen, using the standard MS-DOS type command.                       
                                                                              
   Its argument is passed to MS-DOS for execution.  At the end of the type    
operation the screen will display "Type carriage return to continue:" which   
will return to the IMDISP command mode.  If there is not enough memory        
available for the system command to be executed an error message is           
displayed.                                                                    
                                                                              
                                                                              
4.5.34 NEG                                                                    
                                                                              
                                                                              
   The NEG command is used to invert the current color palette, turning the   
image into a negative.   It takes no keywords or arguments.                   
                                                                              
                                                                              
4.5.35 PLOT                                                                   
                                                                              
   The PLOT command is used to draw plots of image lines and spectra on the   
screen.  If the current file is an image, you must specify which line you     
wish to plot.                                                                 
                                                                              
   PLOT takes the following keywords:                                         
                                                                              
    LIN n      plot line n of the image (required for 2-D files)              
    SYMbol x   draw the plot using character x instead of connecting the      
               points with a line                                             
    ZOOm       prompt user to zoom in on a region of the plot after it is     
               drawn                                                          
    OVErlay    overplot - do not erase the current plot                       
    MAX n      set the maximum y value in the plot                            
    MIN n      set the minimum y value in the plot                            
    COLor n    use DN value n to plot the data                                
                                                                              
  Example:  to compare lines 200 and 210 of the current image on the same     
vertical scale, first plot line 200 (as a line) with the command              
                                                                              
    PLOT LINE 200 MIN 0 MAX 255                                               
                                                                              
   Now overlay the plot of line 210 using "+" signs and color 10 of the       
current palette with the command                                              
                                                                              
    PLOT LINE 210 OVERLAY MIN 0 MAX 255 COLOR 10 SYMBOL +                     
                                                                              
                                                                              
                                                                              
4.6 OTHER UTILITY PROGRAMS                                                    
                                                                              
                                                                              
   There are several utility programs also provided on the distribution       
disk.  These programs can read PDS labeled, VICAR2 labeled, or unlabeled      
images.  The output images are always written with PDS ODL labels.  The       
programs prompt for the necessary input values.                               
                                                                              
                                                                              
4.6.1 COPIM                                                                   
                                                                              
                                                                              
   COPIM is a simple image copying program.  It can copy the whole image,     
for example to put PDS labels on a foreign image), or extract a window from   
the image.  It can subsample the image with an integral subsampling factor.   
The program prompts for the input and output file names, the window to        
extract (just type return for the whole image), and the subsampling factor    
(the default is 1).  If the input file is not in VICAR2 or PDS image format   
the program will also prompt for the number of lines and samples, pixel       
size and header size of the image.                                            
                                                                              
   For example, to extract the first 100 lines and samples from the file      
LOGO.IMG the following commands would be used:                                
                                                                              
   COPIM                                                                      
   Input Image: LOGO.IMG                                                      
   Lines: 350 Samples: 340 Bits per pixel: 1                                  
   Output Image: LOGOSUB.IMG                                                  
   Starting line and sample, number of lines and samples:                     
   1 1 100 100                                                                
   Line Subsampling factor (1): 1                                             
   Sample Subsampling factor(1): 1                                            
                                                                              
                                                                              
4.6.2 CONVERT                                                                 
                                                                              
                                                                              
   CONVERT is simple pixel format conversion program.  It converts an image   
to an integer (16 bits), byte (8 bits), nibble (4 bits), or binary (1 bit)    
image.  It can also perform a user specified scaring.  The program prompts    
for the input and output file names, the output format (must be 1,4,8, or     
16 bits), and the input and output numerical ranges for scaling.  The         
default scaling values are appropriate for the data types being used.         
                                                                              
   For example, to convert MONTAGE.IMG to an 8-bit per pixel image and        
scale the output pixels evenly between the values of 0 and 127 the            
following commands would be used:                                             
                                                                              
   CONVERT                                                                    
   Input Image: MONTAGE.IMG                                                   
   Lines : 350    Samples : 640 Bits per pixel : 4                            
   Output Image: MONTBIG.IMG                                                  
   Output bits per pixel (1, 4, 8, 16) : 8                                    
   Input DN range (O 15) :                                                    
   Output DN range (O 255) : 0 127                                            
                                                                              
                                                                              
                                 Chapter 5                                    
                                                                              
                                  CREDITS                                     
                                                                              
   IMDISP is maintained and updated (since version 4.4) by a small group of   
volunteers -- Mike Martin, Ron Baalke (JPL) and Archie Warnock (ST            
Systems).  It was originally written by Mike Martin, Frank Evans and Dan      
Nakamura of the Jet Propulsion Lab.  The plotting code was written by Ed      
Esfandari (Interferometrics).  Paradise and Trident video drivers were        
added by Gregg Gunnells of the USGS. Jerry McFaul (USGS), Ed Grayzeck (U of   
MD) and Nick Beser (JHU/APL) have been valiant testers of the program         
through its many iterations, and have made many suggestions for               
improvements along the way.                                                   
                                                                              
   IMDISP would not have its current capabilities if it weren't for the       
generous efforts of several software authors who have seen fit to donate      
their work into the public domain.  Through their work, we are able to keep   
IMDISP in the public domain, free to anyone who wants it.  We want to         
publicly thank all of them here:                                              
                                                                              
Gershon Elber     - GIF I/O routines (GIF_LIB.ZIP)                            
Michael Walraven  - High resolution timer (TIMERHI.ZIP)                       
Max Medley        - Mouse interface code                                      
James Birdsall    - EMS, XMS allocation code (EMSLB215.ZIP, XMSLB121.ZIP)     
Marty Del Vecchio - EMS/XMS swap routines (SWAP300.ZIP)                       
                                                                              
   And, of course, we would also like to thank our users, from whom we        
continue to receive ideas, bug reports and fixes.  They exercise the          
program in ways we never imagined.                                            
                                                                              
GIF and 'Graphics Interchange Format' are trademarks of CompuServe,           
Incorporated, an H&R Block Company.                                           
                                                                              
                                  Appendix                                    
                                                                              
                              COMMAND SUMMARY                                 
                                                                              
                                                                              
   Within this command summary listing, brackets ([]) indicate optional       
parameters or keywords.  Filename is the name of a file in the current        
directory or a fully qualified filename which can include drive letter and    
pathname.  Directory name is an MS-DOS directory path specification, a        
valid directory mask a specification containing wild card characters (*, ?)   
per MS-DOS rules for wildcard use in the DIRECTORY command.  The symbol "n"   
is used to indicate an integer value.                                         
                                                                              
  BATCH        [filename]                                                     
  BRIGHTEN     [n]                                                            
  BROWSE       [directory mask] [SIZe n] [SUB n] [NOLabel]  [DNLOw n]         
               [DNHIgh n] [PAUse n] [ALL] [SELect] [FILe] [BUFFERS]           
               [AUToset n]                                                    
  CD           [directory name] [..]                                          
  CHDIR        [directory name] [..]                                          
  COPY         [buffer [TO buffer]] [FILE]                                    
  CURSOR       [DSL n] [DSS n]                                                
  DARKEN       [n]                                                            
  DIRECTORY    [directory mask] [/w]                                          
  DISPLAY      [SUB n] [SL n] [SS n] [NL n] [NS n] [BP n] [CENTer] [DSL n]    
               [DSS n] [FLIP] [NOPrompt] [NOMemory] [AUToset] [SOUrce]        
               [buffer]                                                       
  ENHANCE      [BAAlke] [CONvolution n] [EDGe n] [LOG n] [MEAn n] [MEDian]    
               [POWer n] [STAir n] [SMEar] [SCReen] [UNSharp]                 
  ERASE        [REFRESH] [buffer]                                             
  EXIT         [NOClear]                                                      
  FILE         [filename[.GIF]] ["CD:mm:ss:bb"] [NOMemory]                    
  HELP         [command name]                                                 
  HISTOGRAM    [SUB n] [SL n] [SS n] [NL n] [NS n] [BP n] [CENter]            
               [VOYager] [VIKing] [buffer]                                    
  LABEL                                                                       
  LOG          [ON] [FILe filename] [CLOse] [OFF]                             
  MASK         [LO n [WITH n]] [HI n [WITH n]]                                
  MENU         [filename]                                                     
  MERGE        [buffer [scale] [WITH buffer [scale] [TO buffer]]] [FILE]      
  NEG                                                                         
  OVERLAY      [MAXLAT n] [MAXLON n] [MINLAT n] [MINLON n] [LEGend]           
  PALETTE      [EDIT n] [PS n] [LOAd filename] [SAVe filename] [DISplay]      
               [ERAse] [CYC n [FAST] [TIME n]]                                
  PERSPECTIVE  [SL n] [SCR]                                                   
  PLOT         [LINE n] [SYMBOL x] [COLOR n] [MAX n] [MIN n] [OVERLAY]        
               [ZOOM]                                                         
  PROFILE                                                                     
  QUIT         [NOClear]                                                      
  REFRESH                                                                     
  SAVE         filename[.GIF] [SL n] [SS n] [NL n] [NS n] [BP n]              
               [REFRESH]                                                      
  SET          [DNLO n] [DNHI n] [BROwse filename] [DIS name] [NS n]          
               [PAL dir] [REFresh ON/OFF] [DELay ON/OFF] [PROmpt ON/OFF]      
               [BUFFERS dir]                                                  
  SLANT        [RIGht] [LEFt]                                                 
  STRETCH      [LO n] [HI n]                                                  
  SYSTEM       [MS-DOS command]                                               
  TEXT         [LINe n] [SAMple n] "text" or 'text' [NOPrompt]                
  TYPE         filename