Generating fringe-free images from phase-shifted interferometry data.
Weighted averaging of a sequence of phase-shifted interference patterns yields a fringe-free intensity image that can be useful for machine vision, lateral metrology, defect detection, and other supplementary tasks in a surface-profiling interferometer. Coefficients for effective fringe-removal algorithms follow from a Fourier analysis of phase-shifting errors. Theoretical and experimental examples illustrate the substantially improved performance of a well-designed weighted average over a simple linear sum of data frames.
de Groot
Peter
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Zygo Corporation, Laurel Brook Road, Middlefield, Connecticut 06455, USA.