基于自适应高程约束的TomoSAR三维成像  

Three-dimensional Imaging of Tomographic SAR Based on Adaptive Elevation Constraint

作　　者：任子帅 张照 高雨欣 郭睿 REN Zishuai;ZHANG Zhao;GAO Yuxin;GUO Rui(School of Automation,Northwestern Polytechnical University,Xi’an 710129,China;School of Electronics and Information,Northwestern Polytechnical University,Xi’an 710129,China)

机构地区：[1]西北工业大学自动化学院,西安710129 [2]西北工业大学电子信息学院,西安710129

出　　处：《雷达学报（中英文）》2023年第5期1056-1068,共13页Journal of Radars

基　　金：国家自然基金(42104039,61971326);陕西省自然科学基础计划项目(2023-JC-QN-0370)。

摘　　要：层析合成孔径雷达成像(TomoSAR)是2010年以来SAR成像领域尤其是城市三维成像的热门研究方向。但在TomoSAR三维重建中,相位缠绕会引起高程散射剖面的周期性谱峰,并导致散射体高程向位置的错误估计和三维成像结果中建筑点云的分层,即高程模糊。该文针对这一现象,提出一种自适应调整高程搜索范围的方法,以提升散射体高程估计的准确度,并改善高程模糊。该方法首先进行场景的高度预估计,然后根据高度预估计构建高程采样中心线性函数并计算搜索半径,从而确定并更新各像素的高程搜索范围,保留真实谱峰并隔离模糊峰值。机载和星载的实测数据实验表明所提方法明显改善了高程模糊和伪影问题,提高了三维点云的空间集中度和连续性。Synthetic Aperture Radar Tomography(TomoSAR)has emerged as a hot research topic in the field of SAR imaging,particularly for three-dimensional(3D)urban imaging in recent years.However,in TomoSAR 3D reconstruction,due to the phase unwrapping difficulty,periodic spectral peaks appear in the reconstruction results of the reflectivity profile along the elevation.This results in errors in estimating the elevation locations of the scatterers and causing layering effects in 3D imaging results,which is the elevation ambiguity.In light of this phenomenon observed in TomoSAR,a method for the adaptive adjustment of the elevation search range is proposed to improve the accuracy of the elevation estimation and reduce elevation ambiguity.In this method,the height of the scene is first estimated,the linear function of the elevation sampling center is subsequently constructed based on the height pre-estimations,and the search radius is finally calculated.Thereafter,the elevation search range of each pixel in the SAR image is determined and updated,preserving the true spectral peaks while isolating the ambiguity peaks.The experimental results for airborne and spaceborne measured data demonstrate that the proposed method significantly improves elevation ambiguity and artifacts-related issues while also improving the spatial concentration and continuity of 3D point clouds.

关 键 词：层析合成孔径雷达成像(TomoSAR) 相位缠绕 高程模糊 散射体 高程搜索范围 

分 类 号：TN95[电子电信—信号与信息处理]