改进的枝切法在相位展开中的应用

Application of a Novel Branch-Cut Algorithm in Phase Unwrapping

该文在Goldstein枝切法的基础上提出了一种改进的枝切法。该算法对干涉图中的正负残差点进行组合,再以枝切线的长度和作为评价值对干涉图中的正负残差点进行重新替换组合,使整体枝切线的长度和减小,有效地克服了相位解缠时在残差点密集区易出现的"孤岛现象"问题。仿真数据以及实测数据验证了该算法的可行性和有效性。

Interferometric synthetic aperture radar （InSAR） measures the height of the object based on the distance difference reflected by the absolute phase difference of the corresponding pixels on two pieces of synthetic aperture radar （SAR）. But in fact the phase difference is restricted to （-n, n）, which causes phase wrap. The branch-cut method is one of the most important approaches for the phase unwrapping. In this paper, an improved branch-cut algorithm is proposed based on the Goldstein algorithm. The positive and the negative residues in the interference image are combined in this algorithm and then re-combined and replaced by using the length of the branch-cut as criteria so that the overall length of the branch-cut can be reduced gradually and the ＂isolated island phenomenon＂ in the unwrapping process can be overcome effectively. The proposed method has been verified through both the simulated and experimental data.