From a single-frame dual-wavelength spatial carrier-frequency interferogram (SCFI), we propose a novel phase retrieval method of dual-wavelength interferometry (DWI). First, by continuously moving the intercepted area pixel-by-pixel in a single-frame SCFI along the horizontal and vertical directions, we construct a sequence of phase-shifting sub-interferograms. Second, the wrapped phases of each single wavelength can be retrieved from those phase-shifting sub-interferograms via the least-squares iteration algorithm. Third, the phase of synthetic wavelength can be obtained by subtraction between the wrapped phases of single wavelengths. Both the numerical simulation and the experimental result demonstrate that the proposed method reveals greater accuracy and convenience. Furthermore, because only single-frame SCFI can perform the phase retrieval of DWI, the proposed method offers better ability in resisting external vibration and disturbance, which will greatly facilitate the application of DWI in the dynamic phase measurement.

Combining spatial carrier-frequency phase-shifting (SCPS) technique and Fourier transform method, from one-frame spatial carrier-frequency interferogram (SCFI), a novel phase retrieval method is proposed and applied to dynamic phase measurement. First, using the SCPS technique, four-frame phase-shifting sub-interferograms can be constructed from one-frame SCFI. Second, using Fourier transform method, the accurate phase-shifts of four sub-interferograms can be extracted rapidly, so there is no requirement of calibration for the carrier-frequency in advance compared to most existing SCPS methods. Third, the wrapped phase can be retrieved with the least-squares algorithm through using the above phase-shifts. Finally, the phase variations of a water droplet evaporation and a Jurkat cell apoptosis induced by a drug are presented with the proposed method. Both the simulation and experimental results demonstrate that in addition to maintaining high accuracy of the SCPS method, the proposed method reveals more rapid processing speed of phase retrieval, and this will greatly facilitate its application in dynamic phase measurement.

An independent component analysis-based simultaneous phase-shifting dual-wavelength interferometry approach is proposed. By using a one-time phase-shifting procedure, the simultaneous phase-shifting operation of two illumination wavelengths can be implemented, and then the background intensity and two orthogonal independent components of each single wavelength can be separated from a sequence of simultaneous phase-shifting dual-wavelength interferograms with random phase shifts. Subsequently, the wrapped phases of single wavelength can be calculated by above two orthogonal independent components; thus the unambiguous phase of synthetic wavelength can be achieved. Both the simulation and experimental results show that the proposed approach reveals the advantages of high accuracy, rapid speed, high stability, and good adaptability for arbitrary phase shifts.