Coordinate calculation for direct shape measurement based on optical flow

Abstract

A quite novel surface profilometry is proposed, which adopts a single optical grating projection setup with a small projection angle. The height distribution of the measured surface is retrieved by calculating the coordinates of the intersection between the projecting ray and the observing sight line. While the position of the observing point in the deformed fringe pattern can be detected by fringe optical flow. The relationship between optical flow and the height distribution of the tested surface is established. Simulations and some primary experiment results are completed to prove that the proposed method is feasible to measure a complex surface. The main advantage of the proposed method is obviously that the height distribution of the measured surface can be obtained directly without phase-to-height transformation.