Noise-immune phase unwrapping by use of calculated wrap regions

We implement a proposed method for noise-immune phase unwrapping through the calculation of what may be called wrap regions. The theory of this method is reformulated and discussed with regard to random wrapping, a phenomenon that occurs with diffusely reflecting objects if the optical phase change caused by a deformation is calculated by subtraction of the phases calculated before and after the deformation. Two methods of eliminating random wrapping are presented. The algorithm for phase unwrapping is described, and experimental results are presented. (C) 1997 Optical Society of America.