关键词: 合成孔径雷达, 图像去噪, 非下采样轮廓变换, 邻域收缩

Abstract: Speckle noise in Synthetic Aperture Radar（SAR） images seriously affects the subsequent processing of the SAR image. In order to solve this problem, a denoising method is presented for SAR image which combines median filtering and NeighShrink based on nonsubsampled contourlet transform. The original SAR image is decomposed by NSCT to get the low-frequency subband and high-frequency subband image, and then low-frequency noise in the low-frequency subband is removed by using the median filter. According to the correlation neighbouring coefficients of NSCT decomposition, the high-frequency noise in the high-frequency subband is eliminated by using NeighShrink. Experimental results show that this approach is better than the NeighShrink based on wavelet and the NSCT hard threshold denoising method in denoising performance and visual effects. The proposed denoising method can improve capability in speckle denoising and can protect the texture message better.

Key words: Synthetic Aperture Radar（SAR）, image denoising, Nonsubsampled Contourlet Transform（NSCT）, NeighShrink