Sub-pixel matching method based on epipolar line rectification

In order to improve the efficiency and accuracy of the projected grating three-dimensional measurement system, a sub-pixel matching method based on epipolar line rectification was proposed. Firstly, the epipolar line rectification algorithm was used to transform the bi-stereo geometry into the epipolar standard geometry, so the certain point on the left image had the same horizontal epipolar line with the same row coordinate on the right image. Then, the new phase images of left and right camera were achieved by bilinear interpolation algorithm, and the initial matching points were obtained using the proposed method of stereo matching algorithm based on phase region matching. Thirdly, the local minimum of the surface was achieved by the least squares fitting of 33 neighborhood similarity metric of the initial matching points to be a quadratic surface. Then the right camera matching point coordinate was acquired which had the same phase with the left camera matching point. The planeness of a standard planar was measured to evaluate the accuracy of the proposed method. The results show that the proposed method can achieve the stereo matching fastly and accurately.