融合枝切法和最小费用流的多级相位解缠方法  

Multi-level phase unwrapping method by combining the branch-cut and minimum cost flow

作　　者：花奋奋 王萌萌 于洋 卢丽君[3] 黄国满[3] HUA Fenfen;WANG Mengmeng;YU Yang;LU Lijun;HUANG Guoman(School of Geography,Geomatics and Planning,Jiangsu Normal University,Xuzhou,Jiangsu 221116,China;School of Environment and Spatial Informatics,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Chinese Academy of Surveying and Mapping,Beijing 100036,China)

机构地区：[1]江苏师范大学地理测绘与城乡规划学院,江苏徐州221116 [2]中国矿业大学环境与测绘学院,江苏徐州221116 [3]中国测绘科学研究院,北京100036

出　　处：《测绘科学》2022年第12期138-146,183,共10页Science of Surveying and Mapping

基　　金：自然资源部测绘科学与地球空间信息技术重点实验室经费资助项目(2020-2-2)

摘　　要：针对植被茂盛的山区相位解缠困难、单一方法通用性差等问题,该文提出一种融合枝切法和最小费用流方法的多级相位解缠方法。该方法遵循测量学中“先控制后碎部”原则分区域进行,首先以最小费用流方法解缠的高相干区域作为“控制”,为后续的相位解缠提供初值,其次在低相干区域使用枝切法进行相干阈值递减的多次相位解缠,根据预设的步幅逐步降低相干性阈值,直至终止阈值,其中每一级相位解缠“控制”为高相干区域初值和之前所有级的解缠结果。实验采用两对TanDEM-X Bistatic模式的数据,解缠相位连续,未出现明显的漏洞和相位突变等错误;将解缠相位转换至高程,使用该文方法得到的中误差远小于分别使用枝切法和最小费用流法得到的中误差。该文方法可以充分结合两种解缠算法的优势,在保障解缠区域连通性的同时,避开了叠掩区的影响,也没有向水域等低相干区域过度扩展,有效提高解缠结果的准确性和可靠性。In view of the difficulty of phase unwrapping in lush mountainous areas and the poor universality of a single method,a multi-level phase unwrapping method that combines branch-cut and minimum cost flow was proposed in this paper.This method followed the principle of“control first and then fragments”in surveying.Firstly,the high-coherence region in the interferogram unwrapped by the minimum cost flow method was used as the control information to provide initial values for subsequent phase unwrapping.Secondly,in the low-coherence region,the branch-cut method was used to perform multiple level phase unwrapping with decreasing coherence threshold,and the coherence threshold was gradually reduced according to the preset step until the termination threshold is reached.The phase unwrapping“control”of each stage was the initial value of the high coherence region and the unwrapped results of all previous stages.Two groups of TanDEM-X Bistatic mode data were used for the experiment,the unwrapped phase was continuous and there were no obvious loopholes and phase mutation errors;when the unwrapped phase was converted to the elevation,the RMSE of the proposed method were far less than the branch cutting and minimum cost flow methods.The proposed method could fully combine the advantages of the two unwrapping algorithms;the connectivity of unwrapped phase was ensured and the layover area were avoided,with no excessive expansion to low coherent areas such as water area,which effectively improved the accuracy and reliability of unwrapping results.

关 键 词：多级相位解缠 枝切法 最小费用流 

分 类 号：P237[天文地球—摄影测量与遥感]