Abstract: Due to the speckle noise and imaging conditions,there are great differences between the gray-level-statistics of synthetic aperture radar(SAR) images in the same scene,which makes it difficult for SAR images to realize high-precision registration based on direct application of image features．To solve the problem,we proposed a matching pretreatment algorithm to determine the angle and scale changes of the images by using the statistical analysis of the main line feature information,which can realize matching pretreatment of the images．Experimental results indicate that the algorithm can effectively and accurately find the angle and scale changes of both before and after images change．And while compared to the traditional method of image registration based on direct application of image features,the accuracy and efficiency of the SAR images which are matched by our matching pretreatment algorithm registration are greatly improved.

Key words: SAR image,Main line feature,Histogram,Matching pretreatment