Phase-shifting profilometry for 3D shape measurement of moving objects on production lines

Abstract

It is challenging for phase-shifting profilometry to measure objects in motion on production lines due to two main issues. Firstly, the movement of the object causes a mismatch in its position across different fringe patterns. Additionally, there is a violation of the ideal phase shift between these fringe patterns. To address these problems, we propose a method that takes advantage of the known moving direction of objects on production lines. By aligning the isophase direction of fringe patterns with the known direction of the moving objects, our method essentially solves the well-known phase error problem caused by object motion. Furthermore, we have developed a projection and imaging technique to track the measured object that is covered with different fringe patterns. Both of the previously listed issues have been resolved in this manner. The proposed method is validated by comparisons with state-of-the-art methods, proving its simplicity, broader applicability, and improved measurement accuracy.