Analysis on 3D object measurement based on fringe projection

A coordinate measuring method is presented, which is specially devised to perform the measurement of coordinates with projected fringe techniques of projectors in three dimensions. The system is composed of two parts: one is a target which can move freely in three dimensions, and the other is a stationary two-dimensional array of photodetectors. The mini-projector is tied to the target, and the projected fringe is monitored by the photodetectors. The phase of the photodetectors can be precisely measured with the phase-shifting algorithm, so that, the xyz location of the target can be determined with the geometric model of multilateration using the method of optimization. In this paper, the measuring principle, iterative method, computer simulation and preliminary results are given. The phase-shifting technique has the advantages of high accuracy and noise endurance. The method will provide the basis for follow-up iterative optimization calculation. The experimental results prove that the proposed coordinate measuring method is of high precision.