Phase Error Immunity Optical Measurement System

Abstract

In this paper, a 3D shape measurement system based on a digital fringe projection and phase-shifting technique was described. The fringe generated by a computer was projected onto the object by utilizing a digital video projector. Four steps phase shifting algorithm was used to calculate the 2π wrapping phase, and a heterodyne principle was used to unwrap the phase to obtain the real phase. Then the 3D coordinates object was calculated base on stereo vision algorithm by using the real phase as a constraint. Experiments demonstrated that the system was not sensitive to the phase error caused by the DVP’s nonlinearity.