Abstract: The sparsity of SAR image data was discussed based on the backscattering properties of targets in the image.Firstly,the paper analyzed the cause of sparsity,and pointed out that the sparsity originates from the backscattering properties of the targets,the sparsity of the strong scattering centers,and the roughness of the imaging area. Secondly,the visual differences of the sparse properties between optical and SAR images were compared based on the sparse representations. Thirdly, the application of these sparsity properties to SAR image feature-enhancement was investigated.Finally, the experiments with simulated data and MSTAR data demonstrate the positive effect of sparse constraints on feature-enhancement.

Key words: SAR image, Sparsity, Backscattering, Feature-enhancement