Equivalence of BRISK Descriptors for the Registration of Variable Bit-Depth Aerial Imagery

Using low bit depth images for image processing applications offers a number of advantages over full depth images, reduced data transmission, removal of superfluous detail and improved compressibility with potential reduction in FPGA resource usage for use on-board small UAS platforms. It is demonstrated here that Binary Robust Invariant Scalable Key point (BRISK) descriptors can often be matched directly, without modification, between images with differing number of gray levels (bit-depth). The performance is evaluated within the context of obtaining a sufficient number of control points for an image registration problem. This could be used to determine direct equivalence of an unknown, unaligned, reduced palette image against a known reference image of superior bit-depth.