Three-dimensional reconstruction using phase-shifted square-wave patterns

Among structured light strategies, phase measuring profilometry (PMP) is considered to be an accurate and robust 3D reconstruction method. However, in practical scenes, gamma distortion is an inevitable factor that affects the accuracy and resolution of the final measurement result. In this paper, we propose a square-wave encoding scheme, which is gammafree, and we also demonstrate why the scheme is immune to gamma distortion. Then, based on the epipolar geometry, the invalid phase is removed by the epipolar constraint. Experiments demonstrate that the method can effectively reconstruct the surface of the scanned object and remove the invalid phase. With the proposed method, the accuracy for reconstructing a vertical plane is effectively improved. The method can be an effective alternative in the gamma distorted systems.