Phase-unwrapping algorithm based on frequency analysis for measurement of a complex object by the phase-measuring-profilometry method

摘要

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.