Abstract: Abstract： During planetary landing, it is an effective method to achieve hazard detection and avoidance by analyzing dense digital elevation map getting from two pictures taken by binocular cameras via matching algorithms. The principles of SAD, fullcensus transformation and sparsecensus stereo matchingtechniques are explained. And an improved SAD algorithm and LOG filter are proposed to overcome the weakness that a simple SAD cannot handle the condition when two pictures have different illumination. Then the algorithms are simulated and compared via stereo images from Middlebury College and sandtable pictures. The matching error rate, the realtime and the usability of the different algorithms are discussed in the scene of planetary landing.

Key words: Keywords： hazard detection during planetary landing, stereovision matchingtechniques, SAD, census transformation