Dual-tree complex wavelet coefficient magnitude modelling using the bivariate Cauchy-Rayleigh distribution for image denoising
Dual-tree complex wavelet coefficient magnitude modelling using the bivariate Cauchy-Rayleigh distribution for image denoising
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DOI：
10.1016/j.sigpro.2014.03.028
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发表时间：
2014-12
期刊：
影响因子：
--
通讯作者：
P. Hill;A. Achim;D. Bull;M. Al-Mualla
中科院分区：
文献类型：
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作者：
P. Hill;A. Achim;D. Bull;M. Al-Mualla
小波收缩是自然图像去噪的标准技术。最初提出用于离散小波变换 (DWT) 域内的单变量收缩，通过使用（近似）平移不变小波分解，例如双树复小波变换 (DT-CWT) 和二元收缩，它变得更加有效。使用 DT-CWT 的技术受益于（近似）平移不变性和改进的方向性。然而，这些技术分别使用了复值子带系数的实部和虚部。相反，所提出的工作使用系数幅度来产生一种基于重尾双变量分布（幅度）的新型双变量收缩技术，以提供图像去噪的定量改进。将结果与最先进的非局部均值去噪技术 BM3D 进行比较。少量噪声的 PSNR 结果具有可比性，并且对于大量噪声，PSNR 结果在较小范围内。然而，在许多情况下，当使用基于感知的结构相似性度量 (SSIM) 时，与 BM3D 相比，我们开发的技术在噪声输入范围内提供了改进的结果。从感知上看，与 BM3D 相比，所开发的技术能够保留输入图像的更多高频元素。
Wavelet shrinkage is a standard technique for denoising natural images. Originally proposed for univariate shrinkage within the Discrete Wavelet Transform (DWT) domain it has been made more effective through the use of (approximately) translationally invariant wavelet decompositions such as the Dual-Tree Complex Wavelet Transform (DT-CWT) and bivariate shrinkage. Techniques using the DT-CWT benefit from both (approximate) translational invariance and improved directionality. However, these techniques have used the real and imaginary components of the complex valued subband coefficients separately. The proposed work instead uses coefficient magnitudes to produce a novel bivariate shrinkage technique based on a heavy tailed bivariate distribution (of magnitudes) to provide a quantitative improvement in image denoising.The results were compared to state of the art non-local means denoising technique BM3D. The PSNR results for small amounts of noise were comparable and within a small range for larger amounts of noise. However, when using the perceptually based structural similarity metric (SSIM) our developed technique offers improved results across the range of noise inputs when compared to BM3D in many cases. Perceptually, the developed technique is able to retain a greater quantity of the high frequency elements of the input image compared to BM3D.