Localized compensator phase unwrapping algorithm based on flux conservable solver

Abstract

Phase unwrapping is a critical and challenging step in any phase measurement system. Localized compensator phase unwrapping method (LC) has a good accuracy to regularize singularity for noisy wrapped phase data. Since the LC method can compensate the singularity in limited area to local region around singular points (SPs). However, the LC method has two big problems; firstly it requires large amounts of computational time to produce its unwrapped results. Secondly, this method has limitation of memory shortage if the limited area size including SPs is large, hence the LC method cannot produce unwrapped results. Most of the computational time in LC method is exhausted in the process of fixing numerical error of the compensators that are computed from accumulating the solution of Poisson’s equation using boundary element method and fix errors using singular valued decomposition method. In order to solve the LC method’s problems and improve its performance, we propose a new phase unwrapping algorithm based on computing the compensators of singularity cluster regions directly. In the proposed algorithm, the process of fixing the errors is unnecessary, since it considers the compensators as flux of potential vectors and computes them from solving Poisson’s equation directly. The applicability of the proposed method is tested and evaluated on both simulated and experimental phase data. The unwrapped results show that the proposed algorithm can reduce the computational time; meanwhile, it maintains the same accuracy of unwrapped results as the original algorithm with the localized compensator does.