Fast algorithm for reliability-guided phase unwrapping in digital holographic microscopy

Abstract

A fast reliability-guided phase unwrapping algorithm, using an optimized quality map and combining it with look-up table operation, is proposed for digital holographic microscopy. First, by detecting the residues in the wrapped phase map, an intensity threshold is calculated in the normalized intensity image and the measured region is distinguished into the reliable region and the doubtful region. An optimized quality map is derived by the method in which the intensity values in the reliable region are set to 1 and those in the doubtful region remain unchanged. Then the flood fill algorithm by look-up table is implemented with the optimized quality map to retrieve true phase map. The experimental results demonstrate that not only does the proposed algorithm perform well, but also the speed is significantly faster than that of the conventional flood fill algorithm using insert sorting.