投影栅相移法中的相位波动误差及修正算法研究

Study on Phase Error with Periodic Wave Behavior and a New Algorithm in Projected Grating Phase-Shifting Profilometry

分析了因测量系统非线性响应及局部饱和投影栅图像所导致的相位误差及其波动特性。经过实验验证,四步相移算法在抑制系统非线性响应所引起的相位误差方面优于三步相移算法。通过模拟分析得出,在采用传统相移算法对局部饱和条纹图像分析时,相位误差较大,且相位分布具有周期波动特性。为减小因图像局部饱和而产生的相位误差,文中采用了新的算法提取相位。实验分析结果验证了算法的正确性。

Phase error and its periodic wave behavior caused by system＇s nonlinear response and partial intensity saturation of fringe patterns in projected grating phase-shifting profilometry were studied. Experimental results indicate that the phase error caused by system＇s nonlinear response is effectively restrained by using the four-step phase-shifting algorithm instead of the three-step phase-shifting algorithm. Simulation results show that the phase error caused by partial intensity saturation is effectively affected by saturation degree of fringe patterns and also has periodic wave behavior when a conventional phase-shifting algorithm is applied. To decrease the phase error introduced by the partial saturation, a new phase recovering algorithm is proposed and studied in this paper. The validity of the algorithm is proved by experimental results.