Optical plane calibration method for sheet-of-light 3D reconstruction system based on flexible transformation

Abstract In order to address the problems of cumbersome optical plane calibration steps and low calibration robustness in existing sheet-of-light 3D reconstruction systems, we propose a flexible transform-based calibration method to realize high-precision and robust optical plane calibration. First, based on the principle that the control points are coplanar with the optical plane, the spatial coordinates of feature points in the optical plane are determined within the world coordinate system. Then, by formulating a multi-coefficient, high-order matrix synergy model, we establish a flexible mapping between the control points on the optical plane and their corresponding pixel coordinates in the image plane. Thus, the imaging unit’s aberrations are corrected while completing the coordinate mapping from the imaging plane to the optical plane. The model does not need to calculate the center point of the light stripe, which avoids the influence of the error of the image algorithm on the calibration results. Experimental results show that the calibration method has simple steps and more calibration control points, the average distance residual of the control points is 0.0016 mm, the standard deviation is within 0.3 μm, and the average RMS error is 0.0094 mm.