关键词: 合成孔径雷达, 形态Haar小波, 斑点噪声抑制, 滤波, 细节保持

Abstract: The existing speckle reduction algorithms of Synthetic Aperture Radar (SAR) image can efficiently reduce the speckle effects but unfortunately smear edges and details. A new method, based on morphological Haar wavelet, was proposed. In this method, the SAR image was firstly decomposed by 2-D morphological Haar wavelet. Thus, the edges, details and textures were well preserved in low-frequency sub-band. The speckle noise was mainly distributed in high-frequency sub-bands. Then, the average filtering and median filtering were run on the corresponding high frequency sub-bands according to the noise features. Finally, 2-D morphological Haar wavelet inverse transform was carried on to low-frequency sub-band coefficients and filtered high-frequency sub-bands coefficients to reconstruct SAR image accurately. The experimental results show that the proposed method can not only filter the speckle noise efficiently, but well preserve the image textures and details of SAR image. The proposed method is better than the traditional Lee filtering, Frost filtering, Kuan filtering and wavelet soft-threshold overall.

Key words: Synthetic Aperture Radar (SAR), morphological Haar wavelet, speckle reduction, filtering, detail preservation