Fig. 3: Transiently shadowed regions validation of HORUS images.
From: Peering into lunar permanently shadowed regions with deep learning
Example HORUS images in two different TSRs (transiently shadowed regions); we compare HORUS denoised shadowed images to corresponding shadowed raw NAC EDR (Narrow Angle Camera Experimental Data Record) and sunlit CDR (Calibrated Data Record) images of the same region. We observe that HORUS can image features visible in the corresponding sunlit image down to a certain minimum feature size (TP, true positive, blue). Features that are smaller than this appear faint or do not appear in HORUS at all (FN, false negative, yellow). This minimum size depends strongly on the photon count (digital number, DN). In the examples above, the smallest resolved crater diameter is ~5 m and the smallest resolved boulder diameter is ~4 m. We do not observe false positives other than residual noise. Raw NAC image credits to NASA/LROC/GSFC/ASU.
