基于双树复小波变换的相位保持SAR图像降噪

为更有效地抑制噪声,提出了一种基于非正交复值log-Gabor小波变换的SAR图像斑点噪声消除算法。该算法通过相位保持消噪的门限操作确保相位信息不受破坏。由于用单一的乘性模型或加性模型消除SAR图像的斑点噪声都不能取得很好的效果,为此使用具有平移不变性及更多方向选择性的双树复小波变换图像融合算法,通过选择适当的融合规则,使乘性和加性噪声模型优势互补,就能有效抑制斑点噪声。实验结果显示,这种消噪方法与其他方法相比,有明显优势。

DT-CWT Based Phase Preserving Algorithm for SAR Image Despeckling

In this paper,a despeckling method is proposed for synthetic aperture radar(SAR) images.The method improves the phase preserving method using the non-orthogonal,complex valued,log-Gabor wavelets.Threshold of the wavelet responses in the complex domain ensures the important phase information in the image is not corrupted.The multiplicative and additive speckle noise components play an important role in SAR images,but sparately using the two models cannot result in satisfactory despeckling.The shift invariant dual tree complex wavelet transform(DT-CWT) is used which has an increased directional sensitivity. A wavelet-based image fusion method is developed based on the DT-CWT.Expected denoising performance is achieved through a well-chosen fusion scheme.Experimental results demonstrate that our method outperforms several other despeckling methods such as Frost filtering,Kuan filtering,Lee filtering and median filtering on the test images.