Hybrid cost aggregation for dense stereo matching

Matching cost initialization and aggregation are two major steps in the stereo matching framework. For dense stereo matching, a matching cost needs to be computed at each pixel for all disparities within the search range so that it can be used to evaluate pixel-to-pixel correspondence. Cost aggregation connects the matching cost with a certain neighbourhood to reduce mismatches by a supporting smoothness term. This paper presents a hybrid cost aggregation method to overcome mismatches caused by textureless surface, depth-discontinuity areas, inconsistent lightings in an image. The steps taken to aggregate costs for an energy function include adaptive support regions, multi-path aggregation, and adaptive penalties to generate a more accurate disparity map. Compared with two top-ranked stereo matching algorithms, the proposed algorithm yielded the disparity maps of the dataset in Middlebury benchmark V2 with smaller error ratios in depth-discontinuity regions.