二元树复小波域的局部高斯混合模型图像降噪
Image Denoising Based on Local Mixture Gaussian Model of Dual-tree Complex Wavelet Domain
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摘要: 在复小波域上对观测图像进行一种基于高斯混合模型的后验概率分类,并在每类小波系数的局部邻域估计出局部高斯混合模型的参数,这种参数估计是局部自适应的;然后用该局部高斯混合模型对各个子带系数进行贝叶斯框架下的最大后验概率(MAP)估计,以达到降低噪声的目的.由于这种小波变换具有近似的平移不变性和良好的方向选择性,因此在降噪的同时可以很好地消除主要边缘处的“震铃”效应.实验结果表明;文中算法无论从峰值信噪比还是从主观视觉效果上都要优于一些传统的降噪算法.Abstract: In this paper, an algorithm based on Local Gaussian Mixture Model of Dual-Tree Complex Wavelet Transform is proposed for image denoising. A classification is performed based on posterior probability of the Gaussian Mixture Model, with different class matching different Gaussian model. Then subband coefficients are estimated by using Maximum a Posteriori estimator. As approximate shift invariance and good directionality of DT CWT, it can remove “ringing" of the edge region. Experimental results show an improved denoising performance of PSNR and human vision in comparison with other methods.
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