Phase-shift extraction for generalized phase-shifting interferometry

Abstract

A simple algorithm for blind extraction of phase shifts is proposed for generalized phase-shifting interferometry from only three interferograms. Based on the statistical property of the object wave, the algorithm calculates approximately the involved phase shifts as initial values. The extraction is further improved by an iterative method, considering the fact that the closer the phase shifts approach their real values, the more uniform the reconstructed reference wave will become. The feasibility of this algorithm is demonstrated by both simulation and experiment.

Opposite-view digital holographic microscopy with autofocusing capability

“…37, 38 We note that this requirement can be released by using a larger magnification in the OV-DHM system or utilizing a Slightly-off-axis 4, 30 and on-axis 39, 40 recording scheme. In our experiment, a CCD with pixel size 1/4.4 AU (airy unit, the diameter of the first-order diffraction-limited Airy disc in CCD plane) was used, with which a slight resolution reduction still happen in the case of a large out-of-focus distance.…”

The algorithm of the interference patterns with random phase shifts

“…14 приведена вычисленная по всему полю фаза с использованием трехточечной классической формулы расшифровки с оценкой фазовых сдви-гов [17]. Таким образом, предложенный алгоритм расшифровки для эксперимен-тальных интерференционных картин показывает лучшие результаты по срав-нению с классическим алгоритмом расшифровки, в котором производится оценка величины фазовых сдвигов.…”

Advanced method of phase shift measurement from variances of interferogram differences

“…Many methods for phase-shift estimation by analyzing a number of shifted fringe patterns have been published [2][3][4][5][6][7][8][9][10][11]. Among them are works [2][3][4][5][6][7] relating to generalized interferometry and holography.…”

“…Among them are works [2][3][4][5][6][7] relating to generalized interferometry and holography. This group of algorithms for determining the phase shift is generally based on an iterative least-squares procedure and is time-consuming.…”