A new algorithm for precise determination of the global phase shift between two interferograms is introduced. First we calculate the frame difference between the first and the second interferogram; the difference is multiplied by a properly chosen test phase factor, and then we implement a two-dimensional Fourier transform of the frame difference and calculate the energy of the first positive (or negative) diffraction order. An iterative approach is used for the test phase to ensure that the minimum energy is obtained, and then the correct phase shift value is found. This method is called the energy-minimum Fourier transform method, which is accurate and noise insensitive compared with the single-point Fourier transform method. Both the theoretical analysis and experimental results are given.
© 2003 Optical Society of America
(050.5080) Diffraction and gratings : Phase shift
(070.4560) Fourier optics and signal processing : Data processing by optical means
(120.2880) Instrumentation, measurement, and metrology : Holographic interferometry
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
Cheng-Shan Guo, Zhen-Yu Rong, Jing-Liang He, Hui-Tian Wang, Lü-Zhong Cai, and Yu-Rong Wang, "Determination of Global Phase Shifts Between Interferograms by Use of an Energy-Minimum Algorithm," Appl. Opt. 42, 6514-6519 (2003)