Method and apparatus for measuring similarity using matching pixel count

A stereo disparity between a reference image and a search image for a reference pixel in the reference image is determined by (a) calculating a similarity measure between a reference window including a set of pixels centering on the reference pixel and each of a group of search windows in the search image which is of a same shape with the reference window and displaced from the reference window within a predetermined search range, wherein a matching pixel count, which is the number of pixels in the reference window which are similar in intensity to corresponding pixels in a search window, is used as the similarity measure between the reference window and the search window; and (b) determining a displacement between the reference window and a search window which yields a largest similarity measure as the stereo disparity for the reference pixel.