Least Squares Phase Unwrapping Algorithm Based on Topographic Factors
The phase of complex signals is wrapped since it can only be measured modulo-2; unwrapping searches for the 2-combinations that minimize the discontinuity of the unwrapped phase, as only the unwrapped phase can be analyzed and interpreted by further processing. Weighted least squares phase unwrapping algorithm could avoid errors transmission in the whole phase images, but it could not avoid defect and overlay of interference fringes caused by topographic factors. Therefore, a new phase unwrapping and weights choosing method based on local phase frequency estimate of topographic factors was presented. Experiments show it is an efficient phase unwrapping method which well overcome the defect of under-estimate slopes by least squares algorithm, and has higher accuracy and stability than other methods.
Paul P. Lin and Chunliang Zhang
W. K. Liu et al., "Least Squares Phase Unwrapping Algorithm Based on Topographic Factors", Applied Mechanics and Materials, Vols. 105-107, pp. 1876-1879, 2012