Sources of error in planetary photoclinometry

A quantitative analysis of error sources in 1D planetary photoclinometry is presented. The technique is affected by error sources arising from the spacecraft image, the planetary body, and the scan line orientation. Slope errors are calculated for each of these sources, using examples of Voyager imaging of Ganymede and Viking orbiting imaging of Mars. Slope errors are investigated for a variety of viewing and lighting geometries, slope angles, and slope orientations. The results are broken down into nonsystematic and systematic errors. Derivations that allow the calculation of photoclinometric slope errors for any photometric function are presented, and the implications of these results for 2D photoclinometric techniques are discussed.