A novel method for surface exploration: Super-resolution restoration of Mars repeat-pass orbital imagery

Higher resolution imaging data of planetary surfaces is considered desirable by the international community of planetary scientists interested in improving understanding of surface formation processes. However, given various physical constraints from the imaging instruments through to limited bandwidth of transmission one needs to trade-off spatial resolution against bandwidth. Even given optical communications, future imaging systems are unlikely to be able to resolve features smaller than 25 cm on most planetary bodies, such as Mars. In this paper, we propose a novel super-resolution restoration technique, called Gotcha-PDE-TV (GPT), taking advantage of the non-redundant sub-pixel information contained in multiple raw orbital images in order to restore higher resolution imagery. We demonstrate optimality of this technique in planetary image super-resolution restoration with example processing of 8 repeat-pass 25 cm HiRISE images covering the MER-A Spirit rover traverse in Gusev crater to resolve a 5 cm resolution of the area. We assess the "true" resolution of the 5 cm super-resolution restored images using contemporaneous rover Navcam imagery on the surface and an inter-comparison of landmarks in the two sets of imagery. (C) 2015 The Authors. Published by Elsevier Ltd.