High Accuracy Matching of Planetary Images

We address the question of to what accuracy remote sensing images of the surface of planets can be matched, so that the possible displacement of features on the surface can be accurately measured. This is relevant in the context of the libration experiment aboard the European Space Agency's BepiColombo mission to Mercury. We focus here only on the algorithmic aspects of the problem, and disregard all other sources of error (spacecraft position, calibration uncertainties, etc.) that would have to be taken into account. We conclude that for a wide range of illumination conditions, translations between images can be recovered to about one tenth of a pixel r.m.s.