Ten-meter Scale Topography and Roughness of Mars Exploration Rovers Landing Sites and Martian Polar Regions

Introduction The Mars Orbiter Camera (MOC) has been operating on board of the Mars Global Surveyor (MGS) spacecraft since 1998. It consists of three cameras Red and Blue Wide Angle cameras (FOV=140 deg.) and Narrow Angle camera (FOV=0.44 deg.). The Wide Angle camera allows surface resolution down to 230 m/pixel and the Narrow Angle camera down to 1.5 m/pixel. This work is a continuation of the project, which we have reported previously [2]. Since then we have refined and improved our stereo correlation algorithm and have processed many more stereo pairs. We will discuss results of our stereo pair analysis located in the Mars Exploration rovers (MER) landing sites and address feasibility of recovering topography from stereo pairs (especially in the polar regions), taken during MGS ‘‘Relay-16’’ mode. Method The basis for stereo image processing described in this work are the image correlation tools developed as a part of the VICAR (Video Image Communication And Retrieval) software suite at the Multimission Image Processing Laboratory (MIPL) at JPL. VICAR has been developed since 1966 to digitally process multi-dimensional imaging data. We employed VICAR tools used for geometric rectification (GEOMV) and automatic tiepoint matching (program TRACKER3) with a properly calibrated camera model (SPICE I-kernel, [3]) for MOC Wide and Narrow angle cameras instrument. The basis for robust recovery of tiepoints from two images is the Gruen correlation algorithm [1], which has been implemented in VICAR [5]. TRACKER3 routine provides the most useful interface for the feature tracking and automatic tiepoint identification for stereo processing. This program takes two images as input and automatically finds all tiepoints in the images with accuracy down to about 0.2 of a pixel. The tiepoints can be used for either referencing target image to the reference image, or for detecting change between time separated image sequence. Recovery of topography information from stereo pairs followed standard processing scheme :