ABSTRACT In order to improve speckle noise denoising of block matching and 3D filtering (BM3D) method, an image frequency-domain multi-layer fusion enhancement method (MLFE-BM3D) based on nonsubsampled contourlet transform (NSCT) has been proposed. The method designs an NSCT hard threshold denoising enhancement to preprocess the image, then uses fusion enhancement in NSCT domain to fuse the preliminary estimation results of images before and after the NSCT hard threshold denoising, finally, BM3D denoising is carried out with the fused image to obtain the final denoising result. Experiments on natural images and medical ultrasound images show that MLFE-BM3D method can achieve better visual effects than BM3D method, the peak signal to noise ratio (PSNR) of the denoised image is increased by 0.5 dB. The MLFE-BM3D method can improve the denoising effect of speckle noise in the texture region, and still maintain a good denoising effect in the smooth region of the image.

中文翻译：

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基于块匹配和3D滤波的多层融合增强方法去噪图像散斑噪声

摘要 为了改善块匹配和3D滤波（BM3D）方法的散斑噪声去噪，提出了一种基于非下采样Contourlet变换（NSCT）的图像频域多层融合增强方法（MLFE-BM3D）。该方法设计了一种NSCT硬阈值去噪增强对图像进行预处理，然后在NSCT域中使用融合增强融合NSCT硬阈值去噪前后图像的初步估计结果，最后对融合后的图像进行BM3D去噪处理得到最终的去噪结果。在自然图像和医学超声图像上的实验表明，MLFE-BM3D 方法比 BM3D 方法可以获得更好的视觉效果，去噪图像的峰值信噪比（PSNR）提高了 0.5 dB。