Camera calibration based on phase calibration targets

For traditional camera calibration methods, the calibration accuracy of camera parameters is highly dependent on the feature extraction of the control points of the calibration target. However, due to problems such as perspective and lens distortion, the commonly used checkerboards, circular dots, and other calibration patterns will inevitably undergo large deformation, resulting in a serious impact on the accuracy of the extraction of control points. To solve this problem, a camera calibration method based on active phase calibration targets is proposed. The method uses the MI Pad that can automatically display the structured light patterns as the calibration target. Compared with the method of using a checkerboard calibration target, this method does not require pattern detection and avoids the process of manual marking. Also, based on the phase information of the structured light gratings, a large number of dense, high-precision control point coordinates can be obtained even in areas where the image edge distortion is severe. Not only is it highly automated, but it is also suitable for defocused cameras. Experimental results show that the reprojection error of our method is only one-tenth of the comparison method, and it has better robustness and accuracy.