prysm.x.psi

Phase Shifting Interferometry.

prysm.x.psi.degroot_formalism_psi(gs, ss, cs)

Peter de Groot’s formalism for Phase Shifting Interferometry algorithms.

Parameters:

• gs (iterable) – sequence of images

• ss (iterable) – sequence of numerator weights

• cs (iterable) – sequence of denominator weights

Returns:

wrapped phase estimate

Return type:

ndarray

Notes

Ref “Measurement of transparent plates with wavelength-tuned phase-shifting interferometry”

Peter de Groot, Appl. Opt, 39, 2658-2663 (2000) https://doi.org/10.1364/AO.39.002658

num = sum {s_m * g_m} den = sum {c_m * g_m} theta = arctan(num/dem)

Common/Sample formalisms, Schwider-Harihan five-frame algorithms, pi/4 steps s = (0, 2, 0, -2, 0) c = (-1, 0, 2, 0, -1)

Zygo 13-frame algorithm, pi/4 steps s = (-3, -4, 0, 12, 21, 16, 0, -16, -21, -12, 0, 4, 3) c = (0, -4, -12, -12, 0, 16, 24, 16, 0, -12, -12, -4, 0)

Zygo 15-frame algorithm, pi/2 steps s = (-1, 0, 9, 0, -21, 0, 29, 0, -29, 0, 21, 0, -9, 0, 1) c = (0, -4, 0, 15, 0, -26, 0, 30, 0, -26, 0, 15, 0, -4, 0)