A new phase-unwrapping algorithm based on fringe frequency analysis is presented that will achieve greater automation and precision in measuring complex objects by phase-measuring profilometry (PMP). The new algorithm, which combines digital weighted filtering in the frequency domain and modulation ordering in the spatial domain, can recognize corrupt pixels automatically and produce a better phase-unwrapping path. By frequency weighted filtering, the analysis of fringe frequency is converted into the analysis of fringe modulation. Then, based on a strong correlation between local spatial frequency and the reliability of phase data, ordering of the filtered modulation produces an optimized unwrapping path. Simulation and experiments verify the new algorithm.
© 2001 Optical Society of America
(070.2590) Fourier optics and signal processing : ABCD transforms
(120.2650) Instrumentation, measurement, and metrology : Fringe analysis
(150.6910) Machine vision : Three-dimensional sensing
Lian Xue and Xianyu Su, "Phase-Unwrapping Algorithm Based on Frequency Analysis for Measurement of a Complex Object by the Phase-Measuring-Profilometry Method," Appl. Opt. 40, 1207-1215 (2001)