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

Structured light-based micro three-dimensional (3D) imaging technology is widely used in industrial applications. Using a well-calibrated camera and a projector, it is easy to obtain 3D surface topography of objects. However, single camera-projector pairs suffer from problems caused by shadows and their accuracy is limited due to the restricted field of view. To overcome these issues, this article proposes a multi-projector 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 3D reconstruction and data fusion approach is proposed to obtain high precision and shadow-reduced 3D 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 and root-mean-square error in the measurements to be significantly reduced.