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本文基于ALOS光学影像对2008年5月12日发生的四川汶川大地震灾区进行了震害信息提取。由于本次地震造成了大范围的山体滑坡,我们尝试利用震前和震后获取的ALOS/AVNIR-2影像进行滑坡区域信息提取。首先利用分级方法提取植被和水体信息,对植被和水体进行掩膜之后通过基于像元的分类将裸地信息从震前和震后的影像中提取出来,两幅影像中裸地信息的差异则被认为是滑坡。同时在被滑坡阻塞的河流地区,水平面的上升情况也被提取出来。除此以外本文利用由SRTM获得的DEM数据对坡度和滑坡发生之间的关系进行了研究。
Based on the ALOS optical image, this paper extracts the earthquake damage information from the Wenchuan earthquake in Sichuan on May 12, Due to the massive landslide caused by this earthquake, we tried to extract landslide area information using the ALOS / AVNIR-2 images obtained before and after the earthquake. Firstly, vegetation information and water information were extracted by grading method. After the vegetation and water were masked, the information of bare land was extracted from the images before and after the earthquake by pixel-based classification. The difference of bare land information between the two images Is considered a landslide. At the same time, in the river blocked by the landslide, the rise of the water level is also extracted. In addition, this paper uses DEM data obtained from SRTM to investigate the relationship between slope and landslide occurrence.