Accurate and dynamic 3D shape measurement with digital image correlation-assisted phase shifting

Phase-shifting profilometry (PSP) has been widely used in structured-light (SL) systems for three-dimensional (3D) shape measurements, but the speed of the PSP technique is limited by increased phase-shifting patterns. This paper proposes an accurate and dynamic 3D shape measurement method by projecting only four patterns, including three-step phase-shifting patterns and one speckle pattern. Three-step phase-shifting images are used to obtain the initial unwrapped phase map with phase ambiguity. Based on the principle of digital image correlation and multi-view geometry, the absolute phase can be recovered reliably without requiring any embedded features or pre-defined information of the object. To improve the measurement accuracy, the projector coordinate is used as the measuring coordinate to establish a novel stereo SL system model. By solving a least square solution using the triple-view information, accurate 3D surface data can be reconstructed. The experimental results indicate that the proposed method can perform high-speed and accurate 3D shape measurements with an accuracy of 10.64 mu m, which is superior to conventional methods and has certain instructive significance for 3D profilometry and measurement engineering.

Automated summary

This paper presents a method for accurate and dynamic 3D shape measurements using only four projected patterns, including three-step phase-shifting patterns and one speckle pattern. By utilizing digital image correlation and multi-view geometry principles, the absolute phase can be reliably recovered without requiring any embedded features or pre-defined information. The proposed method achieves high-speed and accurate 3D shape measurements with an accuracy of 10.64 μm, outperforming traditional methods and providing guidance for 3D profilometry and measurement engineering.