Improving measurement accuracy in 3D profilometry

A new algorithm for determining the phase of reference points allows for better calibration. Fringe projection profilometry can provide high-speed sur-face inspection and 3D-shape-measurement capabilities. It has wide applications in the automotive, aerospace, semiconduc-tor, and other industries. In particular, the application of this technology to product-quality inspection and process control can yield tremendous cost savings and reduce lead times. Fringe projection profilometry is based on the principle that periodic fringe patterns can be projected onto an object’s surface, and the distorted patterns caused by its depth variation recorded from different directions. The phase distributions of these pat-terns are often recovered by phase-shifting techniques1, 2 or methods based on Fourier-transformation analysis. To recon