| Description: The exposure_parameter attribute identifies the value supplied to the CRISM instrument to command the exposure time. At a given frame rate identified in frame_rate, there are 480 possible exposure times ranging from 1 to 480. An exposure parameter of 480 yields an exposure time equal to the inverse of the frame rate. An exposure time parameter of 1 yields an exposure time 1/480 as large. For example, at a frame rate of 3.75 Hz, an exposure time parameter of 480 yields an exposure time of 0.26667 sec, whereas an exposure time parameter of 1 yields and exposure time of 0.00056 sec. This parameter is included independently of the exposure time itself because some of the Calibration Data Records (CDRs) are applicable to data taken at a particular exposure parameter. |