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Phase-shifting algorithms for nonlinear and spatially nonuniform phase shifts

1997; Optica Publishing Group; Volume: 14; Issue: 4 Linguagem: Inglês

10.1364/josaa.14.000918

1520-8532

Kenichi Hibino, B. F. Oreb, David I. Farrant, Kieran G. Larkin,

Thermography and Photoacoustic Techniques

In phase-shifting interferometry spatial nonuniformity of the phase shift gives a significant error in the evaluated phase when the phase shift is nonlinear. However, current error-compensating algorithms can counteract the spatial nonuniformity only in linear miscalibrations of the phase shift. We describe an error-expansion method to construct phase-shifting algorithms that can compensate for nonlinear and spatially nonuniform phase shifts. The condition for eliminating the effect of nonlinear and spatially nonuniform phase shifts is given as a set of linear equations of the sampling amplitudes. As examples, three new algorithms (six-sample, eight-sample, and nine-sample algorithms) are given to show the method of compensation for a quadratic and spatially nonuniform phase shift.