Calibration and 3D Reconstruction of Telecentric Structured Light System

Three-dimensional (3D) reconstruction of micromechanical components and semiconductors is the key task of precision manufacturing and inspection. In this paper, a precise and flexible calibration and 3D reconstruction method is proposed for a structured light microscopy (SLM) system with two telecentric lenses. Firstly, a dual-telecentric SLM system consisting of a telecentric camera and a telecentric projector with different magnifications is designed, which not only takes full advantage of the depth of field (DOF), but also could expand the field of view. Secondly, a simple algorithm is proposed for joint calibration of the telecentric camera and projector, by establishing an unambiguous formula for the rotation matrix related to the telecentric imaging system. Thirdly, a 3D reconstruction method is presented for the dual-telecentric SLM system based on the fringe projection profilometry (FPP), which could obtain the reference phase and the relationship between the phase difference and depth. Experimental results well demonstrate the effectiveness and accuracy of the proposed method.