Frequency domain phase extraction algorithm for phase-shifting interferometry with random phase-shifting amount and low-sampling rate

Abstract

To extract the exact phase of the measured object in the environmental conditions with random noise, a novel kind of frequency domain phase extraction method for phase-shifting interferometry with random phase-shifting amount and low-sampling rate is proposed, in which the time-varied intensity signal of an arbitrary pixel of phase-shifting interferograms is cut into a lot of sub-sections intensity signals with the same length, and then the frequency domain weighted stack operation is performed for the corresponding Fourier spectrum of these sub-section intensity signals. Importantly, the phase obtained from the proposed method coincides well with the conventional four-step phase-shifting algorithm, but the requirement for the environmental conditions in the former are greatly lowered than that in the latter, moreover, while the same number of phase-shifting interferograms is employed to perform the phase extraction, the phase measuring accuracy in the proposed method is greatly higher than that in the time domain Fourier transform (TFT) method.