Five-Frame Phase-Shifting Algorithm Based on the Immunity to Phase-Shifting Error

This paper designs a kind of phase shifting algorithm of white light interferometry technology, aiming at high precision measurement of MEMS. Through analyzing the error source of phase shifting in theory, five-frame phase-shifting algorithm based on the immunity to phase-shifting error is presented. In the proposed algorithm, phase shifting distance is set to be lambda/8 per step, and the interference fringe phase is changed pi/2 each time. Measurement accuracy of the algorithm has been verified, through the measurement of the standard bench height which has been authenticated by United Kingdom Accreditation Service. The experimental results show that the proposed algorithm can eliminate the transposition error factor and improve the measurement accuracy. Meanwhile, it also has more powerful effect on noise inhibition, and the measurement repeatability is in sub-nanometer.