Mestre-Quereda Alejandro, Lopez-Sanchez Juan M, Mallorqui Jordi J
Hisdesat Strategic Services S.A., 28046 Madrid, Spain.
Signals, Systems and Telecommunications Group, Institute for Computer Research (IUII), University of Alicante, 03080 Alicante, Spain.
Sensors (Basel). 2022 Nov 10;22(22):8696. doi: 10.3390/s22228696.
A geometrical decorrelation constitutes one of the sources of noise present in Synthetic Aperture Radar (SAR) interferograms. It comes from the different incidence angles of the two images used to form the interferograms, which cause a spectral (frequency) shift between them. A geometrical decorrelation must be compensated by a specific filtering technique known as , the goal of which is to estimate this spectral displacement and retain only the common parts of the images' spectra, reducing the noise and improving the quality of the interferograms. Multiple range filters have been proposed in the literature. The most widely used methods are an filter approach, which estimates the spectral shift directly from the data; a method based on information, which assumes a constant-slope (or flat) terrain; and algorithms, which consider both orbital information and auxiliary topographic data. Their advantages and limitations are analyzed in this manuscript and, additionally, a new, more refined approach is proposed. Its goal is to enhance the filtering process by automatically adapting the filter to all types of surface variations using a multi-scale strategy. A pair of RADARSAT-2 images that mapped the mountainous area around the Etna volcano (Italy) are used for the study. The results show that filtering accuracy is improved with the new method including the steepest areas and vegetation-covered regions in which the performance of the original methods is limited.
几何去相关是合成孔径雷达（SAR）干涉图中存在的噪声源之一。它源于用于形成干涉图的两幅图像的不同入射角，这会导致它们之间出现频谱（频率）偏移。几何去相关必须通过一种称为 的特定滤波技术来补偿，其目的是估计这种频谱位移并仅保留图像频谱的公共部分，从而降低噪声并提高干涉图的质量。文献中已经提出了多种距离滤波器。最常用的方法有：一种 滤波器方法，它直接从数据中估计频谱偏移；一种基于 信息的方法，该方法假设地形具有恒定斜率（或平坦）；以及 算法，该算法同时考虑轨道信息和辅助地形数据。本文分析了它们的优缺点，此外，还提出了一种新的、更精细的方法。其目标是通过使用多尺度策略使滤波器自动适应所有类型的地表变化来增强滤波过程。本研究使用了一对绘制意大利埃特纳火山周围山区的RADARSAT - 2图像。结果表明，新方法提高了滤波精度，包括原始方法性能受限的最陡峭区域和植被覆盖区域。
