Deformation monitoring of single buildings using meter-resolution SAR data in PSI
Deformation monitoring of single buildings using meter-resolution SAR data in PSI
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DOI：
10.1016/j.isprsjprs.2012.06.009
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发表时间：
2012-09-01
影响因子：
12.7
通讯作者：
Bamler, Richard
中科院分区：
文献类型：
--
作者：
Gernhardt, Stefan;Bamler, Richard
本文研究了从空间监测单体建筑物的形状和变形的可行性。该方法是基于融合的持久性散射体（PS）点云从几个堆栈的米分辨率合成孔径雷达（SAR）数据。这种高分辨率图像以及精确的轨道信息可从以下来源获得，例如，TerraSAR-X应用持久散射体干涉测量法（PSI）单独处理堆叠，其提供PS的变形和高度估计。然而，由于相对于其最终真实位置的残余偏移，地理编码的PS点云不能简单地合并在一个公共坐标系中，如UTM。这些偏差源于参考点的高度不确定性，必须在每个堆栈的PSI处理期间进行选择。所提出的方法允许若干PS点云的融合，即，可以恢复正确的参考点高度。该算法基于点云匹配过程，包括确定适当的点对应关系和在最小二乘意义上最小化所有选择的点对之间的距离，此外，从PSI提供的视线变形测量的原始运动矢量的重建是可取的。在垂直和水平方向上分离的运动分量的可用性大大增强了对建筑物和地面变形事件的了解。为此，融合的点云用于运动分量的分解。由于TerraSAR-X的上升和下降叠加对南北方向变形的敏感性有限，运动矢量分量的重建仅限于东西方向和垂直方向的分量。后者估计在一个最小二乘调整，包括所有PS在空间有限的区域内。为了分离运动分量，必须包括来自上升和下降轨道的堆叠的变形估计。后者不能从完全相等的航向航迹的组合中精确地确定，因为视线没有足够的差异。最后，城市地区的变形图可分别显示水平和垂直方向的季节性和线性变形。这些地图包含了关于沉降或隆起以及建筑物因热膨胀而产生的结构应力的重要信息。由于所提出的方法（和第一次），充分和精确的运动估计可用于使用米分辨率合成孔径雷达数据在PSI的单个物体的详细监测。几个例子进行了讨论，使用的结果的运动分量估计的基础上融合的四个数据栈评估PSI。(C)2012年国际摄影测量与遥感学会（ISPRS）由Elsevier B. V.出版，版权所有。
In this paper the feasibility to monitor the shape and deformation of single buildings from space is investigated. The methodology is based on a fusion of persistent scatterer (PS) point clouds obtained from several stacks of meter-resolution synthetic aperture radar (SAR) data. This kind of high resolution imagery as well as accurate orbit information is available from, e.g., TerraSAR-X. The stacks are processed individually applying persistent scatterer interferometry (PSI), which provides deformation and height estimates for the PS. However, the geocoded PS point clouds cannot be simply merged in one common coordinate system, like UTM, by reason of residual offsets with respect to their final true positions. These deviations originate from the height uncertainty of the reference point, which has to be chosen during PSI processing of each stack. The presented methodology allows for a fusion of several PS point clouds, i.e., the correct reference point heights can be recovered. The algorithm is based on a point cloud matching procedure that consists of a determination of appropriate point correspondences and a minimization of the distances between all selected pairs of points in a least-squares sense.In addition, the reconstruction of the original motion vector from the deformation measurements in line of sight provided by PSI is desirable. The availability of separated motion components in vertical and horizontal directions greatly enhances the insights into deformation events at buildings and ground. To this end, the fused point clouds are used for a decomposition of motion components. By reason of the limited sensitivity of ascending and descending stacks of TerraSAR-X to deformation in north-southern directions the reconstruction of motion vector components is restricted to components in west-eastern and vertical directions. The latter are estimated in a least-squares adjustment including all PS within a spatially limited area. Deformation estimates of stacks from ascending and descending tracks must be included in order to separate motion components. The latter cannot be determined precisely from a combination of solely equal heading tracks, as the line of sight does not differ enough. Finally, deformation maps of the urban area are available that separately show seasonal and linear deformation in horizontal as well as vertical directions. These maps comprise important information on subsidence or uplift as well as structural stress at buildings due to thermal dilation. As a result of the presented methodology (and for the first time) sufficient and precise motion estimates are available for a detailed monitoring of single objects using meter-resolution SAR data in PSI. Several examples are discussed using the results of motion component estimation based on the fusion of four data stacks evaluated by PSI. (C) 2012 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS) Published by Elsevier B.V. All rights reserved.