An Improved Real-Time Semi-Global Stereo Matching Algorithm and Its Hardware Implementation

When applied to the real-time stereo matching systems based on Field Programmable Gate Array(FPGA), the Census Transform(CT) algorithm has a high false matching rate in specific areas.In order to improve the matching accuracy, a real-time Semi-Global stereo Matching(SGM) algorithm with highly parallel pipeline structure is proposed.The algorithm takes the combination of the improved Tanimoto distance and the weighted 4-direction Absolute Differences of Gradient(ADG) as the initial matching cost.In the cost aggregation stage, a 4-path SMG algorithm is used.In the disparity computation stage, the winner-takes-all strategy is chosen.Then in the parallax correction stage, the threshold detection algorithm is used to replace the traditional left-right check algorithm. Experimental results show that the proposed algorithm can effectively improve the discrimination between weak texture and edge regions, and reduce the dependence on center point and resource consumption.The average mismatch rate of the algorithm on Middlebury platform is 7.52%, and its matching rate on Xilinx zynq-7000 platform is 98 frame/s.