对移相误差不敏感的四帧相位算法

Four-frame phase-stepping interferometry-base insensitive algorithm to phase-stepping error

应用相移干涉术测量物体表面微观形貌时,相移器的移相误差直接影响测量精度。在四帧干涉图情形下,推导出了对移相误差不敏感的相位解算方法。算法将相移误差因子作为中间可代换变量,它的大小随机变化不影响相位计算结果,即相位计算式与相移误差因子无关。对标准正弦样板进行的实验验证表明,该算法有效地抑制了移相误差对形貌测量的影响,进一步提高了表面微观形貌的测量精度和测量可靠性、提高了测量系统的整体性能指标。

When applying phasestepping interferometry to measure surface geometries, distortion is caused by various factors such as the phasestepping error from the phase shifter. The phasestepping error was eliminated by an algorithm based on a fourframe interferogram. In the algorithm, the phasestepping error gene is considered to be an intermediate value that does not influence the phase result. Experimental results show that the algorithm effectively can improve the measurement accuracy of the phasestepping interferometry. 