Dual-biprism-based coaxial fringe projection system

Abstract

Fringe projection profilometry (FPP) has been widely used for three-dimensional shape measurement because of its simple hardware and high measurement accuracy. However, the use of most FPP systems to measure complex surfaces such as stepped height objects can result in severe occlusion and shadow. To alleviate this problem, a coaxial measurement method based on dual biprisms is presented in this paper. The system is low-cost and easy to implement, and does not require the introduction of mechanical moving parts. Only dual biprisms are introduced into the coaxial system to provide the geometric constraints required for reconstruction. Experimental results on the reconstruction of a surface with significant height changes demonstrate that the proposed method can achieve shadow-free measurements.

An error compensation method for 3D measurement of step edge in fringe projection profilometry

“…Researchers have done a lot of exploration to improve the accuracy of edge measurement like measurement system modification [4], 3D imaging algorithm improvements [5,6], etc. At present, the methods of accuracy improvement on step edge measurement using FPP can be divided into three categories: invalid phases rectification, edge compensation and super-resolution imaging.…”