A Novel Disparity Refinement Method Based on Semi-Global Matching Algorithm

Depth information can be obtained using stereo matching algorithms, which compute the horizontal displacement( disparity) of the corresponding points and convert to depth information using the triangular relation. However, the matching process is challenging with presence of textureless regions. This paper proposes a novel disparity refinement method for stereo matching based on Semi-global Matching (SGM) algorithm for textureless images. To be brief, the SGM algorithm is a high-performance matching algorithm of a stereo image pair and it reaches a tradeoff between matching quality and computing complexity. The main contribution comes from the improvement of matching quality on textureless regions. At the end of SGM, a right-to-left consistency check is performed to remove the invalid pixels in the disparity map. The proposed method is added after the right-to-left consistent check. We assume that the textureless regions in the original stereo pairs are planar. We employ edge detection to extract the textureless regions. The fitting method is employed in horizontal and vertical directions respectively. If the distance of two adjacent edge pixels is sufficiently large, the corresponding line segment will be considered as texturelss. For every texturelss line segment, the RANSAC algorithm is performed on the corresponding line segment in the disparity map. We use the well-known Middlebury dataset to compare our method with the normal SGM and other matching algorithms. It shows that our method performs well for most textureless stereo pairs.