Automated Extraction of Inundated Areas from Multi-Temporal Dual-Polarization RADARSAT-2 Images of the 2011 Central Thailand Flood
Automated Extraction of Inundated Areas from Multi-Temporal Dual-Polarization RADARSAT-2 Images of the 2011 Central Thailand Flood
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DOI：
10.3390/rs9010078
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发表时间：
2017-01
期刊：
影响因子：
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通讯作者：
Pisut Nakmuenwai;F. Yamazaki;Wen Liu
中科院分区：
文献类型：
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作者：
Pisut Nakmuenwai;F. Yamazaki;Wen Liu
本研究探讨了一种新的提取方法，特别是在泰国中部的湄南河流域，几乎每年都发生洪水的SAR图像数据的广泛的洪水。由于2011年的洪水是最大的事件之一，持续时间长，因此有大量卫星观测到它，并提供了图像数据。当时，泰国政府主要利用雷达卫星2号数据提取受灾地区，而ThaiChote-1号图像数据也用作光学辅助数据。在这项研究中，同样的数据也以稍微不同和更详细的方式使用。利用多时相双偏振雷达卫星2号图像，采用基于聚类的阈值分割技术（邻谷强调），建立一个自动提取系统，对水域进行分类。新技术已被提出，以提高分类速度和效率。该技术在整个研究区域选择特定的水参考来估计局部阈值，然后通过区域权重对它们进行平均，以获得整个区域的阈值。利用GeoEye-1和ThaiChote-1卫星的高分辨率光学图像和测量站的水位数据对提取的结果进行了验证。
This study examines a novel extraction method for SAR imagery data of widespread flooding, particularly in the Chao Phraya river basin of central Thailand, where flooding occurs almost every year. Because the 2011 flood was among the largest events and of a long duration, a large number of satellites observed it, and imagery data are available. At that time, RADARSAT-2 data were mainly used to extract the affected areas by the Thai government, whereas ThaiChote-1 imagery data were also used as optical supporting data. In this study, the same data were also employed in a somewhat different and more detailed manner. Multi-temporal dual-polarized RADARSAT-2 images were used to classify water areas using a clustering-based thresholding technique, neighboring valley-emphasis, to establish an automated extraction system. The novel technique has been proposed to improve classification speed and efficiency. This technique selects specific water references throughout the study area to estimate local threshold values and then averages them by an area weight to obtain the threshold value for the entire area. The extracted results were validated using high-resolution optical images from the GeoEye-1 and ThaiChote-1 satellites and water elevation data from gaging stations.