1. A method for determining a disparity vector for a pixel in a right image corresponding to a pixel in a left image in a pair of stereo images, wherein the disparity vector is based on a horizontal disparity and a vertical disparity and the pair of stereo images is unrectified, comprising the steps of: determining a set of candidate horizontal disparities; calculating, for each candidate horizontal disparity, a cost associate with a particular horizontal disparity and corresponding vertical disparities; assigning the vertical disparity associated with a first optimal cost to each candidate horizontal disparity, wherein the candidate horizontal disparity and the vertical disparity yield a candidate disparity vector, and wherein the optimal cost is a least cost determined by a matching function C(x, y|i, j) for a horizontal disparity in a bounded horizontal range x −search ≦i≦+x search and for a vertical disparity in a bounded vertical range y −search ≦j≦y search , and wherein i is a horizontal offset and i is a vertical offset for a pixel in the image at a location (x, y); and selecting the candidate disparity vector with a second optimal cost as the disparity vector of the pixel in the right imager, and wherein the second optimal cost is a least cost determined by the matching function C(x, y|i, j).