Method for large-scale structured-light system calibration

We propose a multi-stage calibration method for increasing the overall accuracy of a large-scale structured light system by leveraging the conventional stereo calibration approach using a pinhole model. We first calibrate the intrinsic parameters at a near distance and then the extrinsic parameters with a low-cost large-calibration target at the designed measurement distance. Finally, we estimate pixel-wise errors from standard stereo 3D reconstructions and determine the pixel-wise phase-to-coordinate relationships using low-order polynomials. The calibrated pixel-wise polynomial functions can be used for 3D reconstruction for a given pixel phase value. We experimentally demonstrated that our proposed method achieves high accuracy for a large volume: sub-millimeter within 1200(H) x 800 (V) x 1000(D) mm(3). (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The proposed method aims to increase the overall accuracy of a large-scale structured light system by multi-stage calibration, calibrating intrinsic and extrinsic parameters separately and establishing pixel-wise phase-to-coordinate relationships using polynomial functions to achieve sub-millimeter high precision within a large volume.