Accuracy improvement for 3D shape measurement system based on gray-code and phase-shift structured light projection

Accuracy is one of the most important features for a 3D shape measurement system based on gray-code and phase-shift structured light projection and it requires accurate modeling and calibration of the camera and projector that consist of the system. In this paper, a new method is proposed to reconstruct the 3D object without the inverse projector model, thus make it possible to use a more accurate projector model considering high to 4th order radial and tangential lens distortion. Moreover, we propose a new system calibration method which can calibrate the camera and projector simultaneously based on the same reference points to eliminate the disadvantage of the conventional two-step calibration methods that the accuracy of the projector calibration is always influenced by the camera calibration error. The experiments compare the performance of our proposed model and calibration method with the conventional ones and the results are presented.