相干变化指数法在震害快速评估中的应用

合成孔径雷达(SAR)具有全天候全天时的特点,为快速展开地震救援,评估震害损失提供了重要的数据支持。本文基于汶川震中东南平原地区的ENVISATASAR影像,利用相位干涉方法处理得到相干变化指数图像,对6个评估区域的像元相干变化指数进行统计分析,以相干变化指数平均值作为区分建筑物基本完好与损毁的阈值,并与实地调查结果相比,精度基本达到70%。验证干涉相干变化指数法对震害快速评估有效的同时,也为震区提供震害救援的依据。

Application of Coherenec Chang e Index Method in Ra pid Earthquake Loss Estimation

The synthetic aperture radar ( SAR) has the characteristics of all-weather and all-time, which can provides important data support for the earthquake relief immediately and assessment of the seismic disaster.Based on the ENVISAT ASAR images of the plains in southeastern Wenchuan-epicenter, this paper employs the coherence images which are obtained by interferometric process-ing with phase information to get coherence change index image.Based on coherence change index of image element analysis about six assessment areas, we got the average of coherence change index as the threshold value to differentiate between intact and damage of buildings.Compared with the result of filed survey, the accuracy of the method that is used in the paper achieved about 70%.The study verified value of coherence change index method for rapid earthquake loss estimation, and it provided great assistance to earth-quake disaster relief.