Improvement of Speckle Reduction Algorithm for SAR Images Based on Mathematical Morphology
Gong Zhang · Nanjing Hangkong Hangtian Daxue xuebao · 2003
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.