基于形态学的SAR图像相干斑抑制算法的改进

在抑制相干斑噪声的同时应尽量保持图像的边缘和纹理特征。基于数学形态学方法的几何滤波算法在有效去除相干斑的同时，能较好地保留图像的边缘特征，但是运算量较大，处理速度较慢，将不利于数据的实时处理。为了克服此缺点，本文应用形态学中平滑方法对该算法作了改进。并对真实SAR图像进行处理并与几何滤波算法及Lee滤波算法处理结果作比较。结果验证了改进算法与几何滤波算法相比在达到同样的处理效果的情况下．减少了一半以上的运算量，大大地缩短了处理时间。

Improvement of Speckle Reduction Algorithm for SAR Images Based on Mathematical Morphology

Speckle, appeared in synthetic aperture radar (SAR) images, is generated by the coherent processing of radar signals and it severely affects the image qualities. To alleviate deleterious effects of speckle, various ways have been devised to suppress it. An ideal algorithm may smooth the speckle without blurring edges and fine details. But most algorithms cannot satisfy these two demands. The geometric filter based on mathematical morphology suppresses the speckle while at the same time preserves the edges and fine detail relatively well. But it is very computationally inefficient, thus having not the potential to achieve real or near real-time processing. To overcome this deficiency, this paper improves the algorithm by morphological opening and closing operations with respect to a structure element. Tests are performed on real SAR images. A set of performance criteria is established and comparisons are made between the improved algorithm and the geometric filter as well as the Lee filter. Result shows the improved algorithm's validity in reducing computational load and its good potential for achieving real-time or nearly real-time processing.