Using the modified local variance method based on different sizes of calculation window, we determine objects after earthquake such as damaged building, intact buildings. By conducting a series of experimental analysis on the aerial and Quickbird image, we obtain that on the Quickbird image the optimal spatial resolution of intact urban buildings is about 2 ~ 3 m and the damage buildings is 2~4 m, on the aerial image the optimal spatial resolution of intact urban buildings is about 3~4 m. The optimal spatial resolution is closely related to the size of the object on the ground. And objects of different sizes have different optimal spatial scale. While processing a large amount of images with high spatial resolution, we choose the optimal spatial scale through resampling. This method can effectively reduce the calculational time on the image and is theoretically meaningful for the application of remote sensing technology to fast assessment of earthquake disaster.%本文基于不同计算窗口大小的改进局部方差方法,判定地震后遥感影像上的目标物,如损毁建筑物、完好建筑物的最佳空间尺度.对航片、QuickBird影像进行了系列实验分析,得到了在QuickBird影像中城区完好建筑物最佳空间分辨率在2～3 m,损毁建筑物最佳空间分辨率2～4 m,航片中城区完好建筑物最佳空间分辨率为3～4 m.最佳空间分辨率与目标地物的尺度紧密相关,不同尺度大小的地物具有不同的最优空间尺度.最佳空间尺度的选择在处理海量高空间分辨率影像时通过重采样选取最佳空间分辨率,可以有效减少图像运算时间,在地震灾害快速评估中具有一定的应用意义.
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