Modified Fourier-transform method for phase-shift calibration

A fast convergent algorithm to accurately measure phase-shift for phase shifter is proposed. In the presence of a spatial carrier frequency, an error function in the Fourier-domain is introduced and then the unknown phase-shift between two phase-shifted fringe patterns is determined by minimization of the error function with the help of a golden section search approach. Compared with the conventional Fourier-transform method, the modified method proposed in the paper is more immune to random noise and hence can give a more accurate result. The translation curve of a liquid-crystal spatial light modulator is also experimentally calibrated.

► We propose a fast convergent algorithm to accurately measure phase-shift for phase shifter. ► With an error function introduced and a golden section search approach the new method can accurately determine the phase-shift from only two fringe patterns. ► With numerical simulations the modified method is more immune to random noise compared with the conventional Fourier-transform method. ► The experiment of phase-shift calibration for a LC-SLM is done to verify the effectiveness of the proposed method.