Fringe patterns in optical metrology systems need to be demodulated to yield the desired parameters. Time-frequency analysis is a useful concept for fringe demodulation, and a windowed Fourier transform is chosen for the determination of phase and phase derivative. Two approaches are developed: the first is based on the concept of filtering the fringe patterns, and the second is based on the best match between the fringe pattern and computer-generated windowed exponential elements. I focus on the extraction of phase and phase derivatives from either phase-shifted fringe patterns or a single carrier fringe pattern. Principles as well as examples are given to show the effectiveness of the proposed methods.
© 2004 Optical Society of America
(100.2650) Image processing : Fringe analysis
(100.5070) Image processing : Phase retrieval
(100.7410) Image processing : Wavelets
(120.3940) Instrumentation, measurement, and metrology : Metrology
(300.6300) Spectroscopy : Spectroscopy, Fourier transforms
Qian Kemao, "Windowed Fourier Transform for Fringe Pattern Analysis," Appl. Opt. 43, 2695-2702 (2004)