Instability of projection light source and real-time phase error correction method for phase-shifting profilometry.

The time-dependent phase error induced by the instability of projection light source (IPLS) is systematically studied for phase-shifting profilometry (PSP). The IPLS of the projection device is investigated by a specially designed experimental setup. Based on the results of the investigation, a new mathematical model to analyze the time-dependent phase error induced by IPLS is established and verified. Two real-time phase error correction methods using a new designed three-dimensional shape measurement system are proposed for the effect of IPLS. Experimental results demonstrate the two methods can effectively eliminate the induced time-dependent phase error with a good robustness and high accuracy. The two real-time correction methods for PSP will be promising for high-accuracy measurements.