Relaxation approach of segment-based stereo matching for urban aerial images

Image matching is the crucial technique of stereo analysis, is also one of the most difficult problems in digital photogrammetry and computer vision, in urban area, because of a large amount of poor-texture areas, discontinued features, occlusion and partly-occlusion between objects increase the extent of difficulty of this problem. To improve the quality of image matching in urban areas, a relaxation approach of segment-based stereo matching is proposed. In this way, line segments are extracted from image by heuristic tracing extraction technique, then the difference of orientation, gradient of line segments and the amount of overlap of segments in the stereo images are calculated and used as the initial probability estimate for each segment match between the stereo pair, then, with the help of constraint of disparity continuity and constraint of consistence of topology, the relaxation process is used to correct the initial probability iteratively until it converge to a steady situation, and the globally optimal match is obtained. In the paper, a brief scheme of probability relaxation for the problem of segment-based stereo matching was firstly given, then the implementation of relaxation stereo matching was described in detail and finally the experimental results and conclusions were presented.