3-D Reconstruction Method for a Multiview System Based on Global Consistency

Structured light-based micro 3-D imaging technology is widely used in industrial applications. Using a well-calibrated camera and a projector, it is easy to obtain 3-D surface topography of objects. However, single camera-projector pair suffers from problems caused by shadows, and their accuracy is limited due to the restricted field of view (FoV). To overcome these issues, this article proposes a multiprojector vision system consisting of a central camera and four surrounding projectors. The global geometry constraint scheme is applied to ensure consistency and stability across multiple projectors, which is achieved by board-to-board pose optimization. In addition, instead of directly using the iso-phase fringe line, geometric plane constraints are used in the calibration process to estimate corresponding projector pixel coordinates. Finally, a triangulation-based 3-D reconstruction and data fusion approach is proposed to obtain high precision and shadow-reduced 3-D surface topography. Experimental results are presented and discussed that demonstrate the good consistency and measurement accuracy of the proposed approach. The global geometry constraint scheme allows relative standard deviation (RSD) and root-mean-square error (RMSE) in the measurements to be significantly reduced.