An Improved Phase Filter for Differential SAR Interferometry Based on an Iterative Method
An Improved Phase Filter for Differential SAR Interferometry Based on an Iterative Method
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DOI：
10.1109/tgrs.2018.2820725
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发表时间：
2018-04
影响因子：
8.2
通讯作者：
Alejandro Mestre-Quereda;J. Lopez-Sanchez;J. Selva;P. González
中科院分区：
文献类型：
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作者：
Alejandro Mestre-Quereda;J. Lopez-Sanchez;J. Selva;P. González
相位质量是用差分合成孔径雷达干涉测量法分析地球表面变形的一个关键因素。各种去相关源可能会降低表面变形估计，因此，这种应用需要相位滤波器。众所周知的Goldstein滤波器由于其简单的实现和计算效率而被最广泛地使用。在过去的几年中，已经提出了改进的滤波器，其基于该滤波器，但在数据处理中引入变化。这些滤波器的有效性主要取决于滤波窗口的大小、平滑频谱的权重以及用于对频谱进行滤波的核。在本文中，我们评估了四个这些过滤器的性能，并提出了一种新的方法，优于所有这些。所提出的滤波器是基于一个迭代的方法，在该方法中，原始相位的去噪与不同大小的自适应滤波窗口逐步。滤波器的有效性由干涉相干性控制，干涉相干性是相位质量的直接指标。此外，我们介绍了一些修改有关的功率谱的处理。具体来说，我们建议使用一个新的滤波器，这是基于切比雪夫插值方案平滑的原始相位。新滤波器的性能已在雷达卫星2号和无人驾驶航空器合成孔径雷达获得的模拟和真实的干涉图上进行了测试，这些干涉图绘制了造成地表变形的两种不同地质事件。
Phase quality is a key element in the analysis of the deformation of the Earth’s surface carried out with differential synthetic aperture radar interferometry. Various decorrelation sources may degrade the surface deformation estimates, and thus, phase filters are needed for this kind of application. The well-known Goldstein filter is the most widely used due to its simple implementation and computational efficiency. In the past years, improved filters have been proposed, which are based on this filter but introduce variations in the data processing. The effectiveness of these filters mostly depends on the size of the filtering window, the weight of the smoothed spectrum, and the kernel used to filter the spectrum. In this paper, we evaluate the performance of four of these filters and present a new method that outperforms all of them. The proposed filter is based on an iterative method in which the original phase is denoised progressively with adaptive filtering windows of different sizes. The effectiveness of the filter is controlled by the interferometric coherence, a direct indicator of the phase quality. Moreover, we introduce some modifications regarding the processing of the power spectrum. Specifically, we propose to smooth the original phase using a new filter which is based on a Chebyshev interpolation scheme. The performance of the new filter has been tested on both simulated and real interferograms, acquired by RADARSAT-2 and the Uninhabited Aerial Vehicle Synthetic Aperture Radar, which mapped two different geological events that caused surface deformation.