Mars 2020 Mission automated color processing of surface images

A human being’s psychological state depends in part on the colors of the surroundings. One of the familiar effects related to this is alertness stimulated by bluish light of high color temperature and induced weariness by reddish low color temperature light such as evening sunlight. Hence, creating images approximating the visual color experience human explorers would have standing on the surface of Mars is an important part of preparing for their first presence there. A professional photographer on Earth uses the combination of two devices, a spectrophotometer and a standardized color reference target, to color ­calibrate the raw image data for recreating the visual experience a visitor would have when standing in the location where a photo was taken. Because neither of these devices has yet been taken to the surface of Mars, an alternative approach is needed to determine a basis for color calibrating Mars surface images. This talk describes a practical approach to color calibrating Mars surface images taken in 1976 by the Viking Lander and images from 2012 until present taken by the Mars Curiosity Rover. As a distinctive feature, the presented approach works primarily using the spectral sensitivity functions (SSF) of the camera sensors and incorporates the non­standard color calibration targets on the Mars landers only as secondary input.