Reduction of the search space region in the edge based stereo correspondence

Usually, the stereo correspondence for a feature point in the first image is obtained by searching in a predefined region of the second image, based on the epipolar line and the maximum disparity. The reduction of the search region can increase the performance of the matching process, in the context of the execution time and the accuracy. For edge-based stereo correspondence, we obtain the relationship between the maximum search space in the second image and the parameters like relative position of the edges, the disparity under consideration and the focal length. Considering the maximum of the disparity gradient in the real scene, we formulate the relation between the maximum search space in the second images with respect to the relative displacement of the continuous edges (as the feature points) in the successive scan lines of the first images. Then regarding the pdf of the disparity gradient, we obtain the maximum of the disparity gradient based on parameters like disparity under consideration and focal length. Finally we develop some very fast stereo matching algorithms, based on the normalized cross correlation criteria (NCC) for different sizes of the matching block