Inverse Rectification for Efficient Procam Pattern Correspondence

A method called inverse rectification, is proposed which facilitates the establishment of correspondences across a projected pattern and an acquired image. A pattern of features comprising vertical dashes is warped by the inverse of the rectifying homography of the projector-camera pair, prior to projection. This warping imparts upon the system the property that projected features will fall on distinct conjugate epipolar lines of the rectified projector and acquired camera images. This reduces the correspondence search to a trivial constant-time table lookup once a feature is found in the camera image, and leads to robust, accurate, and extremely efficient disparity calculations. A projector-camera range sensor is developed based on this method, and is shown experimentally to be effective, with bandwidth exceeding some existing consumer-level range sensors.