[Previous] | [Session 59] | [Next]
S.F. Hviid, W. Markiewicz (Max Planck Institut fuer Aeronomie)
When interpreting Imager for Mars Pathfinder (IMP) images a number of problems have been observed with existing models of the camera geometry. The problems are primarily found when dealing with observations with elevation angles distant from the horizon (El > 20° or El < -20°). The most visual example can be observed when mosaicing images of one of the rover exit ramps. With the existing camera models the images in azimuth along the ramps are projected with a significant offset (3-4 pixels) between the images. Another example can be found at the opposite extreme when interpreting sky observations. Here calculations of the scattering angle give results that are shifted when compared to the observed sky brightness gradient.
A model that fits the observed geometric behavior of the IMP has been developed. The model indicates that the IMP needs to be described as an ``off center" optical system where the optical axis has been shifted away from the center of the CCD by about 45 pixels in both x and y.