This dictionary contains high level classes and attributes used in imaging and spectrometer products. It also contains classes with attributes used during active mission operations. Many of these classes are designed to be extended into local mission dictionaries. ## CHANGE LOG ## 1.4.0.0 - upgraded to v1900 of the IM - removed specific Autoexposure algorithm classes and introduced generic Algorithm_Parameter class - new/improved definitions for Companding_Parameters, Downsampling_Parameters, Exposure_Parameters - removed the following attributes: Data_Correction.data_correction_subtype - removed the following classes because they were insufficiently multi-mission: - Derived_Product_Parameters - Frame_Parameters - Product_Identification - Stereo_Product_Parameters - Vector_Range_Origin - added exposure_type enumeration - new flat_field_algorithm attribute - changed compression_type to compression_class and compression_mode_name to compression_type - added new enumerations for compression_class and compression_type - added new Instrument_Device_Currents class 1.5.0.0 - upgraded to v1A10 of the IM - removed old blocks of commented out XML 1.5.1.0 - changed unit of bandwidth attribute from Units_of_Frequency to Units_of_Length 1.6.0.0 - Upgraded to v1B00 of the IM. - Re-organized attributes into alphabetical order. - Re-organized classes to make most commonly used parts of label easier to find. - Created new classes for housekeeping data (Instrument_State_Parameters, Commanded_Parameters) and placed them at the bottom. - Re-wrote numerous class and attribute definitions, to make dictionary easier for users to understand. - Renamed some classes and attributes to remove redundant words. - Re-designed data correction classes (such as Flat_Field_Correction, Radiometric_Correction, etc.) and other data processing classes such as Companding, Downsampling, etc. to share a common base class. - Renamed Compression class and related attributes to Onboard_Compression_*. This is to make it clear that any image compression was performed for data storage/transmission. PDS4 does not allow compressed images. - Renamed Filter_Parameters to Optical_Filter 1.6.1.0 - Added Brightness_Correction class and associated subclasses/attributes - Added Pointing_Correction class and associated subclasses/attributes (moved from IMG_SURFACE LDD) - Added attributes to Color_Processing class: color_dn_scaling_method, color_dn_scaling_factor - Corrected typo in local_reference_type_check_optical_filter rule The Autoexposure class contains attributes used to identify or describe the algorithm used to automatically calculate the proper exposure time. This is generally based on some kind of histogram analysis. The specific autoexposure algorithm used is defined in the processing_algorithm attribute, and the specific set of attributes needed to describe it will vary based on the algorithm. Examples of autoexposure algorithms include "Maki 2003" used on MER, MSL ECAMs, M2020 ECAMS; "Maurice 2012" used on MSL ChemCam; "Smith 1997" used on Mars Pathfinder Imager. The Brightness_Correction class describes brightness corrections that were applied to an image or mosaic. Brightness correction is the process of adjusting the DN values of adjacent frames in a mosaic so they match visually. It may also involve contrast or vignetting adjustments. The result may no longer be radiometrically calibrated due to the adjustments. The processing_algorithm child of Brightness_Correction describes the type of brightness correction, and should correspond to the classes within Brightness_Correction_Image. If the algorithm is "MIXED", multiple algorithms were used, in which case the specific information in each Brightness_Correction_Image must be used. The Brightness_Correction_File identifies a file containing brightness correction information. The project SIS should define the format of this file. Correction information may appear in the file, in instances of the Brightness_Correction_Image class, or both (if both, they should be consistent). The Brightness_Correction_HSI_Linear class works just like Brightness_Correction_Linear, except that the color image is first converted to HSI (Hue, Saturation, Intensity) space, the correction is applied only to Intensity, and then the result is converted back to RGB space. The Brighness_Correction_Image class describes the brightness correction that was applied to a single image, whether alone or part of a mosaic. The image this correction applies to may be identified via the enclosed Internal_Reference, or via the order in which the Brightness_Correction_Image objects appear (which matches the order given in Input_Product_List). The Brightness_Correction_Linear class describes a simple linear brightness correction, with an additive (brightness_offset) and multiplicative (brightness_scale) factor applied. The result is: output = input * brightness_scale + brightness_offset. If there are multiple bands, the same correction is applied to each band. The Color_Filter_Array class describes whether or not an image was acquired using a Color Filter Array (CFA) and if so, whether and how the CFA pattern was removed. A CFA is a method for making color images using one exposure on a single sensor plane, where microfilters of different wavelengths are put in front of pixels in a specific pattern. The most common pattern is the Bayer pattern, which has a red, blue, and two green pixels in every 2x2 pixel square. Although generally used for RGB color, CFA filters can be of any number and wavelength (see color_filter_array_type). The Color_Processing class contains parameters describing color correction or processing and how the image is represented in color. The Commanded_Parameters class contains attributes used to identify or describe the commands sent to a spacecraft to perform one or more actions resulting in the acquisition of the current data product. These are distinct from similar values in the root Imaging class which indicate the state of the image as acquired. The Companding class describes whether or not data is or has had its bit depth reduced (for example conversion from 12 to 8 bits via a lookup table or bit scaling), the venue where it occurred (Software or Hardware), and the method used to complete the companding. The processing_algorithm attribute specifies how data was companded. Generally this will either be via a lookup table (such as a square root encoding), or by shifting bits to preserve the high order bits and discard the low order bits. The value of this keyword is mission specific but there are recommended values that should apply across missions when possible: NONE - no scaling. LUTn - use the numbered lookup table. Lookup tables are defined in the mission SIS. It is preferred for "n" to be a number but it could be a name, for example LUT_MMM_3 to indicate LUT 3 for the MMM instruments (on MSL). MSB_BITn - Shift to make bit "n" the most significant. Bits start numbering at 0 so MSB_BIT7 means no shift for a 12->8 bit companding, while MSB_BIT11 means to shift right 4 bits for a 12->8 bit companding. AUTOSHIFT - Data should be shifted to preserve the highest value. This value should only appear in a command echo; one of the MSB_BITn values should be used in downlinked data to specify what the actual shift was. The Companding _File class specifies the file containing the decompanding (inverse LUT) table used to process the data. The Correction_Parameter class specifies identifier(s) and value for a data correction parameter applicable to the parent class. The Data_Processing class contains attributes describing how processing and/or calibration was performed on a data product. It is not intended to be used on its own; rather it is intended to be extended by classes specific to a particular type of processing, such as Shutter_Subtraction, Flat_Field_Correction, Companding, etc. The attributes of this class thus become attributes of the extension class. The Data_Processing_File class contain attributes which identify a file containing calibration data that was applied to the science data. It is not intended to be used on its own; rather it is intended to be extended by classes specific to a particular type of file, such as Flat_Field_File. Note that the "name" attribute is the name of the file; this attribute should only be used if the file is either not included in an archive, or if the delivery status is unknown by the data provider. The External_Reference or Internal_Reference class should be used instead of name if at all possible. The Detectorclass contains attributes describing the state of the instrument detector. These are values directly read from the detector and do not necessarily reflect the state of the image after onboard processing. For example, the entire image may be read into memory and then subframed in software, in which case the subframe attributes in this class reflect the entire image (as read from the detector), whereas those in the Subframe class represent the final subframe results. The Device_Component_State class describes the state of one component of an imaging instrument or other imaging device. The meaning of "state" is device-specific. The Device_Component_States class provides a container for the set of states of a component of an imaging instrument or other imaging device. The Device_Current class provides the current of some point on an imaging instrument or other imaging device. The Device_Currents class provides a container for the set of currents of an imaging instrument or other imaging device. The Device_Motor_Count class describes the raw motor count of one actuator on an imaging instrument or other imaging device (such as a filter wheel, focus motor, or zoom motor). This information should typically be reported in a more specific and useable form in other classes, such as a filter number or wavelength in the Optical_Filter class or a focus distnace in the Focus class. The Device_Motor_Counts class provides a container for the set of raw motor counts of actuators on an imaging instrument or other imaging device (such as a filter wheel, focus motor, or zoom motor). The Device_Parameters class identifies where a measurement was made. It may refer to an individual imaging instrument, imaging instrument device, or some defined point on the instrument or device. The class is intended to be extended (for example, by Device_Temperature) to add the associated measurement rather than being used directly. The Device_Temperature class provides a container for the temperature of some point on an imaging instrument or other imaging device. The Device_Temperatures class provides a container for the set of temperatures of an imaging instrument or other imaging device. The Device_Voltage class provides the voltage of some point on an imaging instrument or other imaging device. The Device_Voltage class provides a container for the set of voltages of an imaging instrument or other imaging device. The Downsampling class describes whether or not downsampling occurred, the venue where it occurred (Software or Hardware), the method used to downsample, and the pixel averaging dimensions. A downsampled image is a smaller version of the image, resulting in reduced resolution of the same coverage area. The processing_algorithm attribute specifies the pixel resolution downsample method used. This varies by mission, but examples from MSL include: 'Mean' - Downsampling done in software by calculation of the mean., 'Conditional' - Use hardware binning if downsampling (by mean calculation) and subframe arguments are consistent. The Exposure class contains attributes identifying the image instrument exposure configuration and image exposure values. As a child of the Imaging class, these attribute values identify the actual exposure values when the image was taken. As a child of the Commanded_Parameters class, these attribute values are those that were commanded to the spacecraft at the time the image was taken. The Flat_Field_Correction class specifies how flat-field correction was performed on this image. This can be done either algorithmically, using a Radial_Flat_Field_Correction, or using a Flat_Field_File. The Flat_Field_File class specifies the image used for flat field correction. The image is divided by this flat field image in order to apply the flat field correction (which is the opposite of Radial_Flat_Field_Function). The Focus class contains attributes that describe the focus or autofocus parameters for an observation. As a child of Commanded_Parameters, these indicate the focus settings used to command the instrument. Otherwise, they indicate the actual focus used by the observation. The Focus_Stack class contains attributes that describe a set of images taken at different focus settings, which are often merged to create a best-focus image or combined to extract range information. Focus stacks are also sometimes called ZStacks. The Frame class contains attributes providing information specific to an image frame. A frame consists of a sequence of measurements made over a specified time interval, and may include measurements from different instrument modes. The ICER_Parameters class contains attributes describing onboard compression parameters specific to Joint Photographic Experts Group (JPEG) image compression. ICER is a wavelet-based image compression file format used by the NASA Mars Rovers. ICER has both lossy and lossless compression modes. The Image_Compression_Segment class provides attributes describing each segment into which data was partitioned for error containment purposes as part of the compression process. The Imaging class contains classes and attributes describing both the image product itself and the imaging instrument. Image product information can include exposure duration, filters, data correction, sampling, frame, sub-frames, and how the product was derived. For the imaging instrument, information can be provided describing the dynamic physical or operating characteristics of the imaging instrument. The Instrument_State class contains classes providing the values of any dynamic physical or operating characteristics of the imaging instruments. The JPEG_Parameters class contains attributes describing onboard compression parameters specific to Joint Photographic Experts Group (JPEG) image compression. The JPEG_Progressive_Parameters class contains attributes describing an interlaced progressive JPEG format, in which data is compressed in multiple passes of progressively higher detail. This is ideal for large images that will be displayed while downloading over a slow connection, allowing a reasonable preview after receiving only a portion of the data. The LOCO_Parameters class contains attributes describing onboard compression parameters specific to Low Complexity Lossless Compression (LOCO) image compression, a lossless submode of ICER Used when the list values have no units. The Onboard_Color_Matrix class represents a 3x3 matrix that is used onboard to perform color correction. It is done after de-Bayering, as all three color bands are needed for each pixel. The first three elements are multiplied by the R,G,B (respectively) pixel values and summed to get the output Red pixel value. Similarly, the second three create the output Green, and the last three the output Blue. If the label is not present, no correction was performed. The Onboard_Compression class contains attributes describing the compression performed onboard a spacecraft or instrument for data storage and transmission. The Onboard_Responsivity class specifies factors that have been applied to the R, G, and B cells (respectively) of the Bayer pattern, before de-Bayering (demosaicking) takes place. The intent of these is to approximately balance the filters so the de-Bayering process is not skewed, and EDR/ILT products look reasonable before full radiometric or color correction is done on the ground. If these factors are not present, no correction was performed. The Optical_Filter class defines the filters used by the camera optics (not to be confused with image processing software filters). The filter may be identified by name, identifier, number, or some combination of these. The Pixel_Averaging_Dimensions class provides the height and width, in pixels, of the area over which pixels were averaged prior to image compression. The Pointing_Correction class contains attributes used to identify and describe the camera model transformations completed in order to update pointing information of an image or mosaic. The Pointing_Correction_File class identifies a file containing pointing correction information. The Pointing_Correction_Image class contains attributes used to identify and describe the camera model transformations completed in order to update pointing information of a single image, whether alone or part of a mosaic. The Pointing_Model_Parameter class specifies the name and value (numeric) parameters needed by the pointing model identified by the pointing_model_name attribute in the Pointing_Correction parent class. The meaning of any given parameter is defined by the pointing model. The Radial_Flat_Field_Function class pecifies parameters used to generate a synthetic flat field using a simple radial function of the form: r = (x-x_center)^2 + (y-y_center)^2 ; flat_field(x,y) = 1 + r0 + r1*r + r2*r^2 + r3*r^3 . Note that x is in the sample direction of the image, and y is in the line direction. The image is multiplied by this function in order to perform a flat field correction (which is the opposite of Flat_Field_File). The Radiometric_Correction class is a container for the type and details of the radiometric calibration performed on the product. The Sampling class contains attributes and classes related to the sampling, scaling, companding, and compression or reduction in resolution of data. The Shutter_Subtraction class specifies attributes describing the removal from the image of the shutter, or fixed-pattern. The Subframe class describes the position and other optional characteristics of an image subframe, relative to the original image. The Video class contains attributes related to video observations, defined as a regular time series of frames. The class can be used to describe a single frame within the video, or the video as a whole. This section contains the simpleTypes that provide more constraints than those at the base data type level. The simpleTypes defined here build on the base data types. This is another component of the common dictionary and therefore falls within the common namespace. The active_flag attribute indicates whether or not the data processing described by the parent class is active. In general, the presence of the parent class implies it is active and thus active_flag is optional. The primary purpose for active_flag is to either explicitly indicate a correction is not active (for example, if it normally is but was explicitly turned off), or to be able to provide parameters for historical reasons that may no longer be relevant to a current correction. The analog_offset attribute identifies the analog value that is subtracted from the signal prior to the analog/digital conversion. The auto_exposure_data_cut attribute specifies the DN value which a specified fraction of pixels is permitted to exceed. The fraction is specified using the auto_exposure_data_fraction attribute. The auto_exposure_percent attribute specifies the auto-exposure early-termination percent. If the desired DN (auto_exposure_data_cut) is within this percentage of the measured DN (the DN at which the percentage of pixels above that DN equals or exceeds the auto_exposure_pixel_fraction), then the auto exposure algorithm is terminated and the calculated time is accepted. The auto_exposure_pixel_fraction attribute specifies the percentage of pixels whose DN values may exceed the auto_expsoure_data_cut. The autofocus_step_count attribute specifies the number of steps (images) to be taken by an autofocus algorithm. The autofocus_step_size attribute specifies the size in motor counts of each (or the initial) step taken by the focus adjustment mechanism in an autofocus algorithm. The bandwidth attribute provides a measure of the spectral width of a filter. For a root-mean-square detector this is the effective bandwidth of the filter, i.e. the full width of an ideal square filter having a flat response over the bandwidth and zero response elsewhere. Another common method for measuring bandwidth is Full Width at Half Maximum, which is the width of a "bump" on a curve or function. It is given by the distance between points on the curve at which the function reaches half of its maximum value. The best_focus_distance attribute specifies the estimated distance to best focus. The brightness_offset attribute defines the additive factor used for a linear brightness correction. The brightness_scale attribute defines the multiplicative factor used for a linear brightness correction. The center_filter_wavelength attribute provides the wavelength of the center of the passband, or the peak transmissivity, for an instrument filter. For single-band images, this defines which component of the color space is represented by this band. This keyword is not needed for 3-band images, as all bands are represented. The color_dn_scaling_factor attribute specifies the actual value used to scale the color values. This value is determined using the color_dn_scaling_method. The color_dn_scaling_method attribute defines how the color values are scaled. EXPOSURE_NORMALIZED_COLOR means that the color values have been normalized based on exposure time, so neighboring images in a mosaic will have the same color values. DN_COLOR means that the color values are based on the raw DNs, so images take full advantage of the available dynamic range but may not match with neighbors in a mosaic. Specifies whether the image still has a CFA pattern ("Encoded"), the CFA pattern has been removed ("Decoded") or it never had a pattern ("No CFA"). Defines the type of Color Filter Array (CFA) used to encode multiple colors in a single exposure. The most common example of this is the Bayer pattern. This is optional if there is no CFA. Additional attributes, specific to each CFA type, define whether or not the CFA pattern has been removed, and if so, how (e.g. bayer_algorithm). Defines the color space in which this product is expressed. Some color spaces (e.g. XYZ or xyY) are independent of illuminant, while for others (e.g. sRGB or pRGB) the illuminant matters. It is expected that the defined color spaces will increase over time. The color_subsampling_mode attribute specifies the JPEG color subsampling mode used during compression. Valid values: '4:2:2' - 4:2:2 chroma subsampling, which is the typical case, '4:4:4' - 4:4:4 chroma sampling, which indicates no subsampling, 'Grayscale' - indicates a grayscale image The companding_state attribute specifies whether the data is or has had its bit depth reduced, for example conversion from 12 to 8 bits via a lookup table or bit scaling. Valid values: None - values have not been companded. Companded - values are currently companded. Expanded - values have been companded but are now expanded back to original size. The crosstrack_summing attribute provides the number of detector pixel values in the crosstrack direction that have been averaged to produce the final output pixel. The current_value attribute provides provides the current, in the specified units, of an imaging instrument or some part of the imaging instrument. The decomposition_stages attribute identifies the number of stages of decomposition. The deferred_flag attribute specifies whether compression was done at the time of image acquisition, or was deferred until later (typically at downlink time). The detector_to_image_rotation attribute specifies the clockwise rotation, in degrees, that was applied to an image along its optical path through an instrument, from detector to final image orientation. The device_id attribute supplies the identifier of an imaging instrument, an imaging instrument device, or some point on the instrument or device. The device_name attribute supplies the formal name for an imaging instrument, an imaging instrument device, or some point on the instrument or device. The device_state attribute indicates the state of a sensor or other device associated with the imaging instrument. These states are interpreted in an instrument-specific way. The downtrack_summing attribute provides the number of detector pixel values in the downtrack direction that have been averaged to produce the final output pixel. Defines the gamma value encoded in this image. Gamma correction is used to nonlinearly compress the intensities in an image, and most display systems assume that images are encoded with an sRGB gamma. Note that this is a string value because the most common gamma correction ("sRGB") is not precisely expressible as a gamma exponent. A numeric value indicates a gamma exponent. The erase_count specifies the number of times a detector has been or will be flushed of data in raw counts, dependent on the parent class for the attribute. The error_pixel_count attribute specifies the number of pixels that are outside a valid DN range, after all decompression and post decompression processing has been completed. The exposure count attribute provides the number of exposures taken during a certain interval, such as the duration of one command. For example, this may include the number of exposures needed by an autoexpose algorithm. The exposure_duration attribute provides the amount of time the instrument sensor was gathering light from the scene, such as between opening and closing of a shutter, or between flushing and readout of a CCD. The exposure_duration_count attribute specifies the value, in raw counts, for the amount of time the instrument sensor was gathering light from the scene, such as between opening and closing of a shutter, or between flushing and readout of a CCD. This is the raw count either commanded or taken directly from telemetry as reported by the spacecraft. This attribute is the same as the exposure_duration but in DN counts instead of time, and the translation of exposure_duration_count to exposure_duration will differ by mission. The exposure_duration_threshold specifies the exposure time threshold in raw counts, when shutter_subtraction_mode = 'Conditional'. The exposure_type attribute indicates the exposure setting on a camera. Valid values: 'Manual' - manual exposure setting, 'Auto' - autoexposure is applied by the camera, 'Test' - test exposure setting telling the camera to return a fixed-pattern test image. The filter_id attribute provides a short string identifier for an instrument filter through which an image or measurement was acquired or which is associated with a given instrument mode. The filter_name attribute provides the name, described in the mission documentation, of the optical filter through which an image or measurement was acquired. The filter_number attribute provides the numeric identifier of an instrument filter through which an image or measurement was acquired or which is associated with a given instrument mode. The first_line attribute indicates the line within a source image that corresponds to the first line in a sub-image. The first_sample attribute indicates the sample within a source image that corresponds to the first sample in a sub-image. The focus_merge_blending_flag attribute indicates whether intra-stack image blending has been performed during a focus merge operation. A value of 'false' means images were merged without blending. The focus_merge_registration_flag attribute indicates whether intra-stack image registration has been performed during a focus merge operation. A value of 'true' indicates that intra-stack image registration has been performed during the focus merge operation, while 'false' indicates that images have been merged without translation. The focus_mode attribute specifies the type of focus command, for example: Autofocus, Manual, ZStack, or Relative (focus adjustment based on a previous autofocus). The focus_position attribute defines, in a camera-specific way, the focus metric that should be used for geometric processing of the data (e.g. for creating camera models). This will often be the focus motor count. The focus_position_count attribute specifies a commanded focus, or the initial focus position used by the autofocus algorithm. The focus_stack_flag attribute indicates whether or not focus stack image products were created during the autofocus imaging step. The frame_count attribute indicates the total number of image frames acquired, such as for a video or focus stack observation. The frame_id attribute specifies an identification for a particular instrument measurement frame. A frame consists of a sequence of measurements made over a specified time interval, and may include measurements from different instrument modes. These sequences repeat from cycle to cycle and sometimes within a cycle. The frame_interval attribute defines the time between the start of successive frames in a video product. The frame_rate attribute specifies the calculated frame rate for video products. The frame_type_name attribute specifies whether the image was commanded as part of a stereo pair or as a single left or right monoscopic image. If frame_type = 'Stereo', a left and a right image should be present. The gain_mode_id attribute identifies the gain state of an instrument. Gain is a constant value which is multiplied with an instrument's output signal to increase or decrease the level of that output. These modes may vary by mission so the permissible values should be set by the mission dictionaries. The gain_number attribute specifies the gain value used in the analog to digital conversion. The gain value is a multiplicative factor used in the analog to digital conversion. The gop_frame_count attribute indicates, for video products compressed into a group of images (Group Of Pictures or GOP), the number of images in a GOP. This is not necessarily the total number of frames in the observation (see frame_count), as the observation may consist of a number of GOPs. The gop_frame_index attribute specifies the frame index within a Group Of Pictures (GOP). The height_pixels attribute provides the vertical dimension, in pixels. The icer_quality attribute is a ICER specific variable for on-board ICER data compression. The id attribute supplies a short name (identifier) for the associated value in a group of related values. Defines the illuminant that was used in order to process this image. The valid values are open-ended but examples of valid values include: None, D65, 3000K, 5000K. The interframe_delay attribute provides the time between the end of one frame and the beginning of the next frame in a video product. The jpeg_parameter attribute is a JPEG specific variable which specifies on-board compression determination by image quality or by compression factor, based on a selected on-board compression mode. The jpeg_quality attribute is a JPEG specific variable which identifies the resultant or targeted image quality index for on-board data compression. The line_fov attribute specifies the angular measure of the field of view of an imaged scene, as measured in the image line direction (generally vertical). The lines attribute indicates the total number of data instances along the vertical axis of an image or sub-image. The max_auto_exposure_iteration_count attribute specifies the maximum number of exposure iterations the instrument will perform in order to obtain the requested exposure. The maximum_focus_distance attribute specifies the estimated distance to the farthest pixel with less than 1 pixel of gaussian blur. The minimum_focus_distance attribute specifies the estimated distance to the nearest pixel with less than 1 pixel of gaussian blur. The missing_pixel_count attribute identifies the total number of missing pixels defined by the image or image segment. The motor_count attribute specifies the raw motor counts for the specified device, which indicates the position of the associated mechanism in a device-specific way. Specifies the factor that has been multiplied by the B pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied R and G pixel values to produce the output Blue value. Specifies the factor that has been multiplied by the G pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied R and B pixel values to produce the output Blue value. Specifies the factor that has been multiplied by the R pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied G and B pixel values to produce the output Blue value. Specifies the factor that has been multiplied by the B pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied R and G pixel values to produce the output Green value. Specifies the factor that has been multiplied by the G pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied R and B pixel values to produce the output Green value. Specifies the factor that has been multiplied by the R pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied G and B pixel values to produce the output Green value. Specifies the factor that has been multiplied by the B pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied R and G pixel values to produce the output Red value. Specifies the factor that has been multiplied by the G pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied R and B pixel values to produce the output Red value. Specifies the factor that has been multiplied by the R pixel value after de-Bayering (demosaicking) takes place. This value is summed with the multiplied G and B pixel values to produce the output Red value. The onboard_compression_class attribute identifies the type of on-board compression used for data storage and transmission. Note that the onboard_compression_type identifies the specific compression algorithm used (for example, ICER), whereas the onboard_compression_class gives a simple indicator of the type of compression mode. Valid values: 'Lossless', 'Lossy', 'Uncompressed' The onboard_compression_mode attribute identifies the method used for on-board compression, performed for the purpose of data storage and transmission. The value for this attributes represents the raw integer value for compression, which is then translated to the full name captured by the onboard_compression_type attribute. The onboard_compression_quality attribute is an indication of compression quality, in the range of 0.0 to 1.0. Losslessly compressed or uncompressed data have a value of 1.0. Other values are assigned in a manner specific to the compression mode, but with the property that a higher value means better quality. Although the values are not directly comparable across compression types, this facilitates comparison of compression quality across images independent of compression mode. The onboard_compression_rate attribute provides the average number of bits needed to represent a pixel for image that was compressed on-board for data storage and transmission. The onboard_compression_ratio attribute provides the ratio of the size, in bytes, of the original uncompressed data object to its compressed form (original size / compressed size). Onboard compression is performed for data storage and transmission. The onboard_compression_type attribute identifies the type of on-board compression used for data storage and transmission. Valid Values: 'ICER', 'LOCO', 'JPEG', 'JPEG Progressive', 'MSSS Lossless', 'None'. The pointing_model_name attribute specifies which of several "pointing models" were used to transform the camera model based on updated pointing information. These updates are typically derived from mosaic seam corrections. This attribute and the associated Pointing_Model_Index classes define what the updated pointing information is, providing enough information to re-create the camera model from calibration data. If present, this attribute overrides the default pointing based on telemetry. The special value "NONE" shall be interpreted the same as if the attribute is absent (i.e. the default pointing model should be used). New model names can be created at any time; the models themselves should be described in a mission-specific ancillary file. See also the geom:solution_id attribute within the geom:Camera_Model_Parameters class. The pointing_model_solution_id attribute specifies the identifier of the pointing correction solution used to derive the model specified via the enclosing Pointing_Correction class. This identifier should also appear in the pointing correction file referenced by the Data_Correction_File. If there is only one identifier in the correction file, then pointing_model_solution_id may be omitted. The pointing_model_solution_id attribute may be reused in the context of pointing corrections, although uniqueness is recommended. The pointing correction solution ID namespace is separate from the coordinate system namespace. The processing_algorithm attribute specifies the name of the algorithm used to perform the processing specified by the enclosing class. Algorithm names should be defined in the project documentation, and/or in the enclosing class definition. The processing_venue attribute specifies where the processing described by the parent class was performed. In cases where each pass of a progressive JPEG is downlinked separately, the progressive_stage attribute indicates the highest pass number contained in this image, which indicates the available level of detail. The r0 attribute specifies the 0th-order polynomial coefficient of the function used to describe an algorithmic flat field. See Radial_Flat_Field_Function for the formula. The r1 attribute specifies the 1st-order polynomial coefficient of the function used to describe an algorithmic flat field. See Radial_Flat_Field_Function for the formula. The r2 attribute specifies the 2nd-order polynomial coefficient of the function used to describe an algorithmic flat field. See Radial_Flat_Field_Function for the formula. The r3 attribute specifies specifies the 3rd-order polynomial coefficient of the function used to describe an algorithmic flat field. See Radial_Flat_Field_Function for the formula. The radiometric_type defines the specific type of radiance measurement. Possible values include "Radiance", "Spectral Radiance", "Scaled Spectral Radiance". Note: There are many more possible values, and this definition can be updated to include more examples over time. Defines the scaling factor used for Scaled Radiance or Scaled Spectral Radiance. Scaled radiance is created by dividing radiance by this factor, which scales the radiance to what it would be if the sun were at the zenith with a clear atmosphere. The raw_count attribute provides the value of some parameter measured by a spacecraft or instrument sensor in the raw units reported by that sensor. A separate attribute should be included alongside the raw_count that translates this value into the appropriate engineering units. i.e. temperature_value in degrees C or voltage_value in Volts The readout_rate attribute specifies the clock rate at which values are read from the sensor. Specifies the conversion factor between DN and radiance units that has been applied to the blue channel of an image. Specifies the factor that has been applied to the B cell of the Bayer pattern, before de-Bayering (demosaicking) takes place. Specifies the factor that has been applied to the G cell of the Bayer pattern, before de-Bayering (demosaicking) takes place. Specifies the factor that has been applied to the R cell of the Bayer pattern, before de-Bayering (demosaicking) takes place. Specifies the conversion factor between DN and radiance units that has been applied to the green channel of an image. Specifies the conversion factor between DN and radiance units that has been applied to a panchromatic image. Specifies the conversion factor between DN and radiance units that has been applied to the red channel of an image. The sample_bit_mask attribute Specifies the active bits in a sample. Any bit mask is valid in an non-raw product. Any 8-bit product, whether a scaled raw product or other, will have the value "2#11111111" and be stored in one byte. Any 12-bit product, whether an unscaled raw product, or an ILUT partially-processed product (see companding_method), will have the value "2#0000111111111111" and be stored in two bytes. A 15-bit product (e.g. Radiometrically-corrected Calibrated product type) will have the value "2#0111111111111111" and be stored in two bytes. Any 32-bit integer product (e.g. Histogram Raw product) will have the value "2#11111111111111111111111111111111" and be stored in four bytes. For floating-point data, sample_bit_mask is not valid and may be absent. If present, it should be ignored. NOTE: In the PDS, the domain of sample_bit_mask is dependent upon the currently-described value in the sample_bits attribute and only applies to integer values. The sample_bits attribute specifies the logical or active number of bits in the data, which is distinct from the physical number of bits (for example, encoding 12-bit data within 16-bit words). These logical bits are stored in the low order (least significant) bits, with unused bits filled with 0 (or 1 for negative integers to preserve a two's complement representation). This is distinct from the valid data range (specified by valid_minimum and valid_maximum in Special_Constants class) because all values, including missing/invalid flag values, must fit within the sample_bits. The intent is that the data should be able to be sent through a communication channel that passes only sample_bits with no loss in fidelity. The sample_fov attribute specifies the angular measure of the field of view of an imaged scene, as measured in the image sample direction (generally horizontal). The samples attribute indicates the total number of data instances along the horizontal axis of an image or sub-image. The sampling_factor attribute provides the value N, where every Nth data point was kept from the original data set by selection, averaging, or taking the median. When applied to an image object, the single value represented in sampling_factor applies to both the lines and the samples. The segment_count attribute identifies the number of segments into which the image was partitioned for error containment purposes. The segment_number attribute identifies which compression segment is described in the current Segment class. The segment_quality attribute identifies the resultant or targeted image quality index for on-board ICER data compression. Upon return by the ICER decompress function, the output quantity segment_quality provides an indication of the quality of the reconstructed segment. Specifically, the value returned is a double for which the integer values correspond to attained min loss values, but in general is an interpolation between these values. Thus lower values of segment_quality correspond to higher reconstructed qualities, and a value of indicates lossless compression. Note that the compressed stream does not directly contain the value of min loss that was given to the compressor, but the decompressor does know how far along in the decompression process it got before it ran out of bits; this information is used to determine segment_quality. In rare circumstances the decompressor m ay not be able to determine segment_quality for a segment that it decompresses. In this case it sets segment_quality to 1.0. The reconstructed segment might be either lossy or lossless when this occurs. The technical condition under which a quality value is not determined is that the decompressor runs out of the data for the segment before decoding any bit plane information. The segment_status attribute provides a bit mask which provides the status of decoding for the compression segment identified by segment_number. Upon return by the ICER decompress function, the output quantity of segment_status contains a number indicating the decode status. The decode status may have one or more of the following flags set: SHORTDATASEG FLAG (bit 0): If this flag is set, then the segment contained so little data that nothing could be reconstructed in the segment. INCONSISTENTDATA FLAG (bit 1): If this flag is set, then one or more pieces of information in the segment header (specifically, image width, image height, n segs, wavelet filter, n decomps) are inconsistent with the value(s) in the first (valid) segment. ICER will ignore the data in this segment. DUPLICATESEG FLAG (bit 2): If this flag is set, then the segment index given in the header equals that given by a previous segment. The decompressor will ignore the data in this segment. BADBITPLANENUMBER FLAG (bit 3): If this flag is set, then an ICER internal parameter in the header for this segment has probably been corrupted. The decompressor will ignore the data in this segment. BADBITPLANECOUNT FLAG (bit 4): If this flag is set, then an ICER internal parameter in the header for this segment has probably been corrupted. The decompressor will ignore the data in this segment. BADDATA FLAG (bit 5): If this flag is set, then either the parameter combination given in the header for this segment are not allowed by ICER, or the segment number is bad. This probably indicates corrupted data. The decompressor will ignore the data in this segment. The sequence_number attribute supplies the sequence identifier for the associated value in a group of related values. The shutter_subtraction_mode specifies whether shutter subtraction will be performed, or if it is dependent on the exposure_duration_threshold_count. The subframe_type attribute specifies the method of subframing performed on the image. These methods may vary by mission so the permissible values should be set by the mission dictionaries. Example values from MSL include a) 'Software Only' - Software processsing only. b) 'Hardware Compatible' - Use hardware only if compatible. c) 'Hardware Else Software' - Use hardware then software. d) 'Subframe Around Sun' - If the sun is found, send a subframed image of the sun. If sun is not found, send back no image. The temperature_status attribute defines the status of the associated temperature measurement. The status is interpreted in a device-specific way, but generally 0 indicates a successful measurement. The temperature_value attribute provides the temperature, in the specified units, of some point on an imaging instrument or other imaging instrument device. The value_number attribute provides the value with no applicable units as named by the associated id, name, or sequence_number. The value_string attribute provides the value with no applicable units as named by the associated id, name, or sequence_number. The video_flag attribute indicates whether or not video products were commanded. The voltage_value attribute provides provides the voltage, in the specified units, of an imaging instrument or some part of the imaging instrument. The wavelet_filter attribute specifies thefilter used in the compression and decompression algorithm. The width_pixels attribute provides the horizontal dimension, in pixels. The x_center attribute specifies the sample coordinate of the center of the function used to describe an algorithmic flat field. See Radial_Flat_Field_Function for the formula. The y_center attribute specifies specifies the line coordinate of the center of the function used to describe an algorithmic flat field. See Radial_Flat_Field_Function for the formula. [ { "dataDictionary": { "Title": "PDS4 Data Dictionary" , "Version": "1.11.0.0" , "Date": "Thu Jun 06 15:42:29 PDT 2019" , "Description": "This document is a dump of the contents of the PDS4 Data Dictionary" , "PropertyMapDictionary": [ ] } } ]