Improving calibration accuracy of structured light systems using plane-based residual error compensation

The performance of a structured light system (SLS) highly depends on its calibration especially in applications such as surface metrology and product quality control where high accuracy is required. Motivated by building a real-time highly accurate flatness measurement system, we propose a plane-based residual error compensation algorithm for improving the calibration accuracy of SLSs. Following the highly accurate procedure of geometric calibration using circular control points, the proposed algorithm enforces the planar constraint on the three-dimensional reconstruction of the circular control points, which are projected on a perfect plane, to further reduce the residual calibration error. Our method compensates for the largest proportion of the residual error, in most cases being the model error of the lens distortion in the system. Experimental results show that the compensation elevates the calibration accuracy to a higher level-the planarity error is reduced by 70% and this accuracy is comparable to a well-reputed industrial mechanical measuring machine.