1673-159X

CN 51-1686/N

非下采样Shearlet域多变量模型的图像去噪

Image Denoising Using Multivariate Model Based on Non-subsampled Shearlet Transfrom

  • 摘要: 为有效去除含噪图像中的噪声,提出一种基于非下采样剪切波域的多变量阈值收缩去噪方法。首先考虑图像的非下采样剪切波邻域系数的依赖关系,由最大后验估计推导出多变量收缩函数,估计原始图像的非下采样剪切波系数,其中最高尺度系数结合硬阈值估计,然后经过非下采样剪切波逆变换得到去噪后的图像。该模型充分利用了非下采样剪切波的平移不变性、对图像边缘及纹理细节的表示能力,以及非下采样剪切波系数在尺度内和尺度间的依赖关系。实验结果表明,该方法在有效去除噪声的同时,克服了伪吉布斯效应,保持了图像的边缘及纹理细节。

     

    Abstract: In order to denoise the noisy image, a new image denoising method based on a multivariate shrinkage model in the non-subsampled shearlet (NSST) domain is proposed. A multivariate shrinkage model which takes into account the NSST coefficients'relationship was derived by using maximum a posterior estimator. Then, the noise-free coefficients were estimated by the multivariate shrinkage function. And the highest scale coefficients were estimated by hard-shrinkage method. Finally, the inverse NSST was applied to these estimated shearlet coefficients to obtain the denoised image. The proposed model utilizes the shift-invariance and the sparse representation of NSST, as well as the interscale and intrascale dependency correlation of NSST coefficients. Experiment results show that the proposed method can effectively remove the noise and avoid Gibbs phenomenon while preserving edges and texture details.

     

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