Principal component analysis based simultaneous dual-wavelength phase-shifting interferometry

Combing a sequence of simultaneous phase-shifting dual-wavelength interferograms (SPSDWIs) and principal component analysis (PCA) algorithm, we propose a novel phase retrieval approach in dual-wavelength interferometry. Firstly, for each wavelength, two mutually orthogonal principal component maps are constructed from a sequence of SPSDWIs through using the PCA algorithm, in which SPSDWIs are captured using a monochrome CCD and random and unknown phase shifts. Subsequently, the wrapped phases of each wavelength are obtained directly from the two orthogonal maps by performing the arctangent operation. Finally, an unambiguous phase of an extended synthetic beat wavelength is determined by a simple subtraction between these two wrapped phases. Both, the simulation and the experimental results demonstrate that the proposed approach reveals the simple and convenient performance, faster computing speed and good accuracy.