Fast semi-global stereo matching via extracting disparity candidates from region boundaries

This study proposes a novel fast stereo matching algorithm via semi-global energy optimisation, which achieves a considerable improvement in efficiency for just a small price in accuracy. Based on some assumptions, the authors discover that at most two disparity candidates for each scanline segment of reference image can be extracted. With this observation, the authors present a disparity candidate extraction algorithm. This algorithm constructs an energy function based on colour consistency and restrictions between region boundaries. In this approach, the energy function is optimised via the graph-cuts technique, and the pixels involved are only those positioned on region boundaries, which results in greatly reduced vertex number in the constructed graph and subsequently improved efficiency. After that, a simple partial occlusions handling is conducted as a post-processing to enhance the accuracy of the final disparity map, by selecting a right disparity for each segment from extracted candidates. The performances of our method are demonstrated by experiments on the Middlebury test set.