Depth-Reliability-Based Stereo-Matching Algorithm and Its VLSI Architecture Design

A low-complexity depth-reliability-based stereo-matching algorithm and an efficient scanline memory-merging implementation scheme are proposed in this paper. The developed algorithm analyzes the accuracy of disparity results by using simple local window-based methods and preserves reliable information only. A bidirectional depth propagation flow is then adopted to fill the unreliable segments by using reliable information. Moreover, a set of predefined function-specific reliability variables are extracted to further improve depth quality in the occluded and smooth regions, which can reduce 39% bad pixels obtained by applying the basic $7\times 7$ window-based matching. The proposed scanline memory-merging scheme along with data prefetching can lead to 32.7% savings on the scanline memory area and relax the requirements of external frame buffer size and bandwidth. Experimental results show that the implemented stereo-matching hardware has a gate count of 223 k including the scanline memory, and can achieve up to 70 frames/s for $480\times 540$ resolution ( $2\times 2$ downsampling of FullHD side-by-side 3-D format) with 56 disparity levels.