| Phase unwrapping is a key technique in optics phase measurement, which affects the accuracy of data processing directly. Phase unwrapping method has broad application fields and high practical values, the application fields mainly include Synthetic aperture radar (SAR), synthetic aperture sonar, acoustic imaging, microwave interferometry and magnetic resonance imaging (MRI) etc.The existing phase-unwrapping algorithm can be divided into three categories. The first is path-following methods, and its typical representatives are Goldstein branch-cut algorithm, quality-guided algorithm, mask-cut algorithm and Flynn’s minimum discontinuity approach. The second is minimum-norm method, and its typical representatives are unweighted least-squares phase unwrapping and weighted least-squares phase unwrapping. The third is minimum cost network flow algorithm.Basic principles and current situation of phase unwrapping algorithm are firstly introduced in this paper, including several classical algorithms. The introduction includes detailed algorithms description and sketches.Then, least-square phase unwrapping by means of DCT/FFT algorithm, branch-cut algorithm, quality guide algorithm, mask-cut algorithm, Flyn algorithm, and PCG iteration algorithm were analyzed and programmed in C++ language.Two different kinds of experiments were carried out based on the previous work. One is testing the unwrapping result, including the experiment in ideal mode free from noise, experiment under different noises degree and experiment of isolated point in noise disturbed area. The other is focused on the efficiency of unwrapping algorithms, which includes the calculation of the complexity of theoretical experiments, the efficiency of unwrapping the data of deferent leveled noises and the pixels of different numbers.In order to put phase unwrapping algorithm into more practical applications, the interface of phase unwrapping program was finished and described in detail in this paper. |
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