High-accuracy projector calibration method by reducing perspective transformation error

This paper proposes a novel projector calibration method to improve the calibration accuracy of digital light processing (DLP) projector. The existing projector calibration methods usually fix the position of the camera and projector without considering the effects caused by the perspective projection error of the captured images. By fixing the position of the camera image plane parallel to the calibration board and the camera image centre cocentre to the calibration board centre, the proposed method essentially reduces the perspective transformation error and effectively reduces the distortion of the extracted marker points. The proposed projector calibration procedures are given as follows: Firstly, the optical axis of the camera is adjusted parallel to the normal of the hollow ring calibration board and cocentre to the calibration board, and a texture image is captured by the camera; Secondly, the horizontal and vertical fringe patterns with nine different positions and directions are projected onto the calibration board, and nine sets of projected images are taken; Finally, a one-to-one correspondence between the camera and the projector is established, and the projector is accurately calibrated by using the phase equivalence. The experimental results show that the proposed projector calibration method is feasible and easy to operate, which can essentially reduce the perspective transformation error to improve the calibration and measurement accuracy.