共查询到20条相似文献,搜索用时 15 毫秒
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Multidimensional Systems and Signal Processing - Non-local means (NLM) method is a powerful technique in the field of image processing. The center weight CW (the weight of the pixel to be denoised)... 相似文献
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传统的彩色图像去噪算法通常是分层处理的,而忽略了彩色图像RGB通道之间的相关性,因此基于RGB通道联合相似度估计提出了一种新的彩色图像非局部均值去噪方法。在用非局部均值滤波对彩色图像进行去噪时,首先以目标像素为中心确定其支撑区域,然后根据多通道联合相似度估计确定权重,最后采用逐块滤波的方法对每一层进行滤波。并且针对彩色图像中含有的高斯噪声提出了一种新的噪声参数估计方法。由实验结果可以看出该算法比传统的去噪算法在PSNR和FSIM方面都有提高。因此可以看出在图像去噪过程中考虑三通道之间的相关性是必要的,同时也证明了算法的有效性。 相似文献
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《现代电子技术》2017,(17):36-39
图像去噪是数字图像处理过程中的一个重要步骤,它将直接影响到图像处理的最终质量。针对传统的全变分(TV)正则化去噪算法容易产生阶梯效应的缺点,利用双边滤波去噪算法在空间域和值域两个方面进行滤波的特点,提出一种结合TV模型的双边滤波方法,该方法能在一定程度上有效地改善阶梯效应。仿真实验结果表明,提出的去噪方法不仅能够获得较好的去噪效果,还能有效地保持图像的边缘特征信息,降噪效果明显。在较高水平噪声情况下,与TV算法相比,该方法针对小尺寸灰度图片(256×256)图像的峰值信噪比(PSNR)提高1.45 d B左右,大尺寸灰度图片(512×512)图像的PSNR提高2.56 d B左右。 相似文献
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为消除基于图像处理的刀具磨损检测中的图像噪声,提出了结合非下采样Shearlet变换(Non-subsampled Shearlet Transform, NSST)和快速非局部均值(Fast Non-local Means, FNLM)滤波的图像去噪方法。首先,利用基于决策的非对称剪切中值(Decision Based Un-symmetric Trimmed Median, DBUTM)方法滤除图像中的椒盐噪声;然后,对图像进行NSST多尺度分解,得到一个低频子带和一系列高频子带;最后,分别使用FNLM滤波和各向异性扩散模型调整低频和高频子带系数,并由调整后的各子带系数重构出噪声滤除后的图像。实验结果表明,与基于小波的阈值收缩方法、基于Contourlet的全变差模型结合各向异性扩散方法、基于NSST和标准非局部均值滤波方法相比,本文方法在主观视觉去噪效果、峰值信噪比、结构相似度以及处理速度等4个方面性能更优。 相似文献
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B. K. Shreyamsha Kumar 《Signal, Image and Video Processing》2013,7(6):1211-1227
Non-local means filter uses all the possible self-predictions and self-similarities the image can provide to determine the pixel weights for filtering the noisy image, with the assumption that the image contains an extensive amount of self-similarity. As the pixels are highly correlated and the noise is typically independently and identically distributed, averaging of these pixels results in noise suppression thereby yielding a pixel that is similar to its original value. The non-local means filter removes the noise and cleans the edges without losing too many fine structure and details. But as the noise increases, the performance of non-local means filter deteriorates and the denoised image suffers from blurring and loss of image details. This is because the similar local patches used to find the pixel weights contains noisy pixels. In this paper, the blend of non-local means filter and its method noise thresholding using wavelets is proposed for better image denoising. The performance of the proposed method is compared with wavelet thresholding, bilateral filter, non-local means filter and multi-resolution bilateral filter. It is found that performance of proposed method is superior to wavelet thresholding, bilateral filter and non-local means filter and superior/akin to multi-resolution bilateral filter in terms of method noise, visual quality, PSNR and Image Quality Index. 相似文献
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针对医学磁共振(Magnetic Resonance,MR)图像 中存在Rician噪声较大以及双域滤波算法对Rician噪声处理不彻底、 运行时间较长的缺点,提出一种双域滤波与引导滤波相结合的快速医学MR 图像去噪算法。 该算法将引导滤波边缘保持后 的图像作为双域滤波算法的原引导图像,减少双域滤波算法的迭代次数,缩短算法运行时间 ;然后通过改进算法权重,结合 原始权重系数和指数核函数,构造新的权重系数,对噪声进行有效处理。实验结果表明,本 文算法能有效去除医学MR图 像噪声,保护图像细节,相比优秀的医学MR图像去噪算法,具有更高的峰值信噪比和结构 相似度;且相比经典双域滤波 算法,改进后的算法能将运行时间减少1/3,相比非局部均值算法, 可减少1/2。 相似文献
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目前红外图像广泛应用于各个领域,但受限于探测单元的非均匀性,使得红外图像具有低信噪比、视觉效果模糊的缺点,严重影响其在高端领域中的应用。常用的去噪算法无法兼顾降噪平滑和边缘细节的保持,针对这一问题,文中提出了一种基于引导滤波的多分支注意力残差去噪网络。根据引导滤波原理设计一种引导卷积模块,同时为了兼顾提取浅层和深层特征设计了多分支注意力残差模组。通过实验证明加入新模块后的网络不仅可以有效地实现红外图像降噪,而且能最大程度地保持图像中的边缘细节信息,提升视觉效果,同时在PSRN和SSIM指标上也有良好的表现。 相似文献
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针对红外图像中的混合噪声,提出了一种自适应混合双边滤波算法。首先对双边滤波原理进行了分析,提出不能滤除强高斯噪声和脉冲噪声是由于双边滤波引入灰度域权值而带来的固有不足,因此根据双边滤波算法的特点设置了一种像素间的相似度,并以该相似度为基础将双边滤波不能滤除的强噪声点进行了标记,仅对红外图像中标记出的强噪声点进行中值滤波以减少图像模糊,对普通噪声点采用灰度方差自适应双边滤波以保留更多边缘特征。自适应混合双边滤波能够有效滤除红外图像中的高斯噪声、脉冲噪声以及由其组成的混合噪声,同时在滤波过程中并不降低双边滤波保留红外图像边缘特征的性能。仿真实验结果表明,与传统双边滤波、改进的双边滤波以及各项异性扩散-中值滤波算法相比,该算法无论是滤除红外图像的混合噪声还是保留边缘特征都较为优越。 相似文献
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为了解决高动态红外图像在常规显示设备上显示时对比度低、细节模糊等问题,提出了一种基于双边滤波的红外图像非线性细节增强及动态范围压缩方法。首先利用基于扫描行的均值及标准差的统计方法对图像中的条纹噪声进行检测及插值补偿。然后对高动态红外图像进行双边滤波,得到基频分量及细节分量。针对基频分量动态范围大的特点,压缩其动态范围,对细节分量则进行非线性增强。最后将压缩后的基频分量和非线性增强后的细节分量合成,并将灰度范围调整到8位,得到适合显示的低动态范围图像。实验结果表明,提出的方法能在压缩图像动态范围的同时有效实现图像细节信息的增强。 相似文献
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文中提出了一种广义变分正则化的红外图像噪声抑制方法,该方法采用p-范数代替目前广泛被采用的全变分范数作为正则项,构造了用于抑制图像噪声的展平泛函,从而将图像噪声抑制问题转化为能量泛函优化问题。通过推导,得到了相应的用于图像噪声抑制的非线性偏微分方程,并采用固定点迭代算法进行线性化求解,使得迭代解稳定收敛。数值试验结果表明,该方法能够有效地去除图像噪声,较之全变分图像噪声抑制方法,新方法进一步提高了对小宽度图像边缘的保持能力,是一种有效且性能优良的红外图像噪声抑制方法。 相似文献
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《AEUE-International Journal of Electronics and Communications》2014,68(1):37-43
In this work, a curvelet based nonlocal means denoising method is proposed. In the proposed method, the curvelet transform is firstly implemented on the noisy image to produce reconstructed images. Then the similarity of two pixels in the noisy image is computed based on these reconstructed images which include complementary image features at relatively high noise levels or both the reconstructed images and the noisy image at relatively low noise levels. Finally, the pixel similarity and the noisy image are utilized to obtain the final denoised result using the nonlocal means method. Quantitative and visual comparisons demonstrate that the proposed method outperforms the state-of-art nonlocal means denoising methods in terms of noise removal and detail preservation. 相似文献
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针对太赫兹图像分辨率差,噪声严重和信噪比低等不足,提出了一种基于自适应流形高维滤波的太赫兹图像降噪算法。算法利用中值滤波滤除太赫兹图像的强噪声点,再利用自适应流形高维滤波去除图像中的大部分噪声,最后通过基于拉普拉斯高斯算子的边缘增强对二次滤波后的结果图像进行图像增强。实验结果表明,该算法对于太赫兹图像有良好的降噪效果,在滤除图像中噪声的同时,图像的边缘和细节部分也得到了较好的保留。 相似文献
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分析了非下采样Contourlet变换,利用基于冗余结构的非线性提升方法实现了平移不变的不可分离小波变换,提出了一种改进的非下采样Contourlet变换理论(NSCT-I).NSCT-I具有更好的细节捕捉能力、平移不变性、良好的多分辨率、局部化和多方向性,能够获得更好的图像处理效果.在分析现有阈值函数和阈值选择方法的基础上,构建了适合NSCT-I变换方法的阈值函数,提出了一种基于NSCT-I的收缩阈值去噪算法.分析和仿真实验表明:该算法具有良好的去噪效果和保持细节的性能. 相似文献
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基于去频谱混叠Contourlet变换的层内局部相关性图像降噪 总被引:2,自引:0,他引:2
提出了一种基于去频谱混叠Contourlet变换的层内局部相关性图像降噪新方法.含噪图像经抗混Contourlet多尺度变换,得到一个低频逼近子图和一系列不同尺度、不同方向的高频细节子图,充分利用变换域同层同方向子带内信号系数相关性强、噪声系数无相关性的特点,采用强局部化零均值高斯分布模型对高频细节子图进行降噪处理.实验结果表明,该方法计算效率高,能克服Contourlet变换中的频谱混叠,避免了重构图像出现"划痕"现象.无论是PSNR指标,还是在视觉效果上,该方法的去噪性能均好于Contourlet去噪、Contourlet域HMT去噪和基于抗混叠Contourlet变换的硬阈值去噪,在有效去噪的同时,具有很好的图像边缘和细节保护能力. 相似文献
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Lorenzo-Ginori J.V. Plataniotis K.N. Venetsanopoulos A.N. 《Vision, Image and Signal Processing, IEE Proceedings -》2002,149(5):290-296
The problem of phase image denoising through nonlinear (NL) filtering is addressed. There are various imaging systems in which the phase information is utilised to generate useful imaging data. However, the presence of noise makes difficult to obtain the appropriate phase image. The authors apply NL vector filtering techniques to denoise the complex data from which the phase image is extracted. A study was realised in which several NL filters were applied to a simulated complex image. The effects of filtering were determined through a Monte Carlo simulation in which the image was successively contaminated with six different noise models. The effectiveness of the filters was measured in terms of normalised mean square error, signal-to-noise ratio and the number of eliminated phase residues. Results indicate a significant noise reduction, especially when NL filters based on angular distances are applied to the noisy input. 相似文献
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The resolution and quality of the depth map captured by depth cameras are limited due to sensor hardware limitations, which becomes a roadblock for further computer vision applications. In order to solve this problem, we propose a new method to enhance low-resolution depth maps using high-resolution color images. The structural-aware term is introduced because of the availability of structural information in color images and the assumption of identical structural features within local neighborhoods of color images and depth images captured from the same scene. We integrate the structural-aware term with color similarity and depth similarity within local neighborhoods to design a local weighting filter based on structural features. To use non-local self-similarity of images, the local weighting filter is combined with the concept of non-local means, and then a non-local weighting filter based on structural features is designed. Some experimental results show that super-resolution depth image can be reconstructed well by the process of the non-local filter and the local filter based on structural features. The proposed method can reconstruct much better high-resolution depth images compared with previously reported methods. 相似文献