多山地区SAR数据的预处理是实践应用中的关键。基于GAMMA平台,研究微波遥感数据的辐射定标、多视处理、滤波、正射校正和辐射校正等预处理方法和流程,为有关研究的进一步开展提供基础数据。辐射定标使SAR图像真实地反映地面目标后向散射特性;Gamma-map滤波既能很好地平滑图像去除斑点噪声,又能很好地保持边缘和纹理细节,目视效果较好;基于DEM模拟影像的正射校正方法原理清晰,效果较好;辐射校正可以消除因地形引起的辐射畸变。
SAR data preprocessing is the most important part of the practical application in hilly regions. Based on the GAMMA platform,SAR data radiometric calibration,multi- look processing,filtering and Ortho- rectification was presented. Provided the basic data for the further research. Radiometric calibration made a true reflection of the ground target backscatter characteristics. Gamma- map filter can well smoothed the SAR image,and can preserve the edge and texture details. The principle of Orthorectification of SAR image in mountain area by DEMwas clear,and the rectification errors were less than one pixel. Radiometric correction eliminated SAR radiometric distortions which were induced by terrain.