Cancellation of Scattering Mechanisms in PolInSAR: Application to Underlying Topography Estimation
Cancellation of Scattering Mechanisms in PolInSAR: Application to Underlying Topography Estimation
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DOI：
10.1109/tgrs.2012.2205157
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发表时间：
2013-02
影响因子：
8.2
通讯作者：
C. López-Martínez;K. Papathanassiou
中科院分区：
文献类型：
--
作者：
C. López-Martínez;K. Papathanassiou
本文研究了干涉复相关的极化依赖性，并提出了一种方法，用于取消个人的散射机制，在复相关系数相位，在地面模型的随机体积的假设下。这使得能够估计森林和植被地区的地面地形。分析的第一部分考虑了体积与地面的分离（包括双反弹散射机制）。该过程识别偏振状态，而不将它们约束为在两个偏振采集中相等，这允许消除体积散射贡献或地面贡献。为了获得剩余或隔离的散射机制的干涉相位，必须在第二步骤中去除该散射机制的偏振相位贡献。就森林地区而言，以前的方法是从两个不同的角度考虑的。对于下伏地面地形的估计，体积散射贡献的消除使得可以访问与地面贡献相关联的干涉相位。另外，基于地面贡献的抵消来估计与体积散射贡献相关联的干涉测量信息。所提出的技术进行了分析的基础上的模拟和实验偏振干涉合成孔径雷达数据，表明地面地形，以及与体积贡献的高度，是渐近无偏的，并依赖于随机体积的颗粒的形状。在球体（η = 0）的情况下，地面与体积的比值较大，有利于地形相位的准确估计。对于偶极类粒子（η = 0.5），基态体积比减小，产生相干性|ρ|在0.1的量级，使得需要大的散斑滤波以获得地形相位的可靠估计。
This paper investigates the polarimetric dependence of the interferometric complex correlation and proposes a methodology for cancelling individual scattering mechanisms, in terms of the complex correlation coefficient phase, under the assumption of the random volume over ground model. This allows the estimation of the ground topography on forested and vegetated areas. The first part of the analysis considers the separation of the volume from the ground (including the double-bounce scattering mechanism). This process identifies the polarization states, without constraining them to be equal in both polarimetric acquisitions, which allow to cancel either the volume scattering contribution or the ground contribution. In order to have access to the interferometric phase of the remaining or isolated scattering mechanism, the polarimetric phase contribution of this scattering mechanism has to be removed in a second step. In the case of forested areas, the previous methodology is considered from two different point of views. For the estimation of the underlying ground topography, the cancellation of the volume scattering contribution makes possible to access the interferometric phase associated to the ground contribution. In addition, the interferometric information associated to the volume scattering contribution is estimated based on the cancellation of the ground contribution. The proposed techniques are analyzed on the basis of simulated and experimental polarimetric interferometric synthetic aperture radar data, demonstrating that the ground topography, as well as the height associated to the volume contribution, are asymptotically nonbiased and dependent on the shape of the particles of the random volume. In case of spheres (η = 0) , the ground-to-volume ratio presents large values favoring the accurate estimation of the topographic phase. For the case of dipole like particles (η = 0.5), the ground-to-volume ration decreases producing a coherence |ρ| in the order of 0.1, making necessary a large speckle filtering to obtain a reliable estimation of the topographic phase.