We propose an innovative hybrid real-time vision system concept for autonomous landing on planetary bodies. It contains digital and optical processing methods. It includes high speed digital image warping to preprocess a video image for optical correlation, position estimation by synthetic estimation filtering, image stabilization by joint transform optical correlation, and hazard identification from measurements of optical flow by sequential image subtraction.
Richard D. Juday,
"Hybrid Vision For Automated Spacecraft Landing", Proc. SPIE 1053, Optical Pattern Recognition, (29 June 1989); doi: 10.1117/12.951525; https://doi.org/10.1117/12.951525