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It has recently been proved that the popular nonlocal means (NLM) denoising algorithm does not optimally denoise images with sharp edges. Its weakness lies in the isotropic nature of the neighborhoods it uses to set its smoothing weights.…

Statistics Theory · Mathematics 2012-12-04 Arian Maleki , Manjari Narayan , Richard G. Baraniuk

The Non-Local Means (NLM) image denoising algorithm pushed the limits of denoising. But it introduced a new paradigm, according to which one could capture the similarity of images with the NLM weights. We show that, contrary to the…

Statistics Theory · Mathematics 2013-11-18 Simon Postec , Jacques Froment , Béatrice Vedel

In this letter, we investigate the shrinkage problem for the non-local means (NLM) image denoising. In particular, we derive the closed-form of the optimal blockwise shrinkage for NLM that minimizes the Stein's unbiased risk estimator…

Computer Vision and Pattern Recognition · Computer Science 2015-05-05 Yue Wu , Brian Tracey , Premkumar Natarajan , Joseph P. Noonan

A new multiscale implementation of non-local means filtering for image denoising is proposed. The proposed algorithm also introduces a modification of similarity measure for patch comparison. The standard Euclidean norm is replaced by…

Computer Vision and Pattern Recognition · Computer Science 2013-04-04 Zahid Hussain Shamsi , Dai-Gyoung Kim

Nonlocal patch-based methods, in particular the Bayes' approach of Lebrun, Buades and Morel (2013), are considered as state-of-the-art methods for denoising (color) images corrupted by white Gaussian noise of moderate variance. This paper…

Computer Vision and Pattern Recognition · Computer Science 2016-12-14 Friederike Laus , Mila Nikolova , Johannes Persch , Gabriele Steidl

This paper introduces a new approach to non-local means image denoising. Instead of using all pixels located in the search window for estimating the value of a pixel, we identify the highly corrupted pixels and assign less weight to these…

Computer Vision and Pattern Recognition · Computer Science 2017-10-04 Hamid Reza Shahdoosti

In Non-Local Means (NLM), each pixel is denoised by performing a weighted averaging of its neighboring pixels, where the weights are computed using image patches. We demonstrate that the denoising performance of NLM can be improved by…

Computer Vision and Pattern Recognition · Computer Science 2017-02-17 Sanjay Ghosh , Amit K. Mandal , Kunal N. Chaudhury

We propose an adaptive approach for non local means (NLM) image filtering termed as non local adaptive clipped means (NLACM), which reduces the effect of outliers and improves the denoising quality as compared to traditional NLM. Common…

Computer Vision and Pattern Recognition · Computer Science 2014-12-10 Raka Kundu , Amlan Chakrabarti , Prasanna Lenka

In this article we derive an unbiased expression for the expected mean-squared error associated with continuously differentiable estimators of the noncentrality parameter of a chi-square random variable. We then consider the task of…

Applications · Statistics 2012-10-15 Florian Luisier , Thierry Blu , Patrick J. Wolfe

A new image denoising algorithm to deal with the Poisson noise model is given, which is based on the idea of Non-Local Mean. By using the "Oracle" concept, we establish a theorem to show that the Non-Local Means Filter can effectively deal…

Applications · Statistics 2013-09-18 Qiyu Jin , Ion Grama , Quansheng Liu

In this paper, we propose a new image denoising method, tailored to specific classes of images, assuming that a dataset of clean images of the same class is available. Similarly to the non-local means (NLM) algorithm, the proposed method…

Computer Vision and Pattern Recognition · Computer Science 2017-06-22 Milad Niknejad , Jose M. Bioucas-Dias , Mario A. T. Figueiredo

A new image denoising algorithm to deal with the additive Gaussian white noise model is given. Like the non-local means method, the filter is based on the weighted average of the observations in a neighborhood, with weights depending on the…

Other Statistics · Statistics 2011-11-04 Qiyu Jin , Ion Grama , Quansheng Liu

This paper describes a novel theoretical characterization of the performance of non-local means (NLM) for noise removal. NLM has proven effective in a variety of empirical studies, but little is understood fundamentally about how it…

Statistics Theory · Mathematics 2012-04-27 Ery Arias-Castro , Joseph Salmon , Rebecca Willett

We propose a new image denoising algorithm when the data is contaminated by a Poisson noise. As in the Non-Local Means filter, the proposed algorithm is based on a weighted linear combination of the bserved image. But in contract to the…

Applications · Statistics 2012-01-31 Qiyu Jin , Ion Grama , Quansheng Liu

The generic risk estimator addresses the problem of denoising images corrupted by additive white noise without placing any restriction on the statistical distribution of the noise. In this paper, we discuss an efficient FPGA implementation…

Image and Video Processing · Electrical Eng. & Systems 2023-01-13 Rinson Varghese , Chandrasekhar Seelamantula , Rathna G N , Ashutosh Gupta , Debajyoti Dhar

The acquisition of MRI images offers a trade-off in terms of acquisition time, spatial/temporal resolution and signal-to-noise ratio (SNR). Thus, for instance, increasing the time efficiency of MRI often comes at the expense of reduced SNR.…

Computer Vision and Pattern Recognition · Computer Science 2011-10-28 Sudipto Dolui , Alan Kuurstra , Iván C. Salgado Patarroyo , Oleg V. Michailovich

Image denoising is a classical signal processing problem that has received significant interest within the image processing community during the past two decades. Most of the algorithms for image denoising has focused on the paradigm of…

Computer Vision and Pattern Recognition · Computer Science 2020-08-26 Varuna De Silva

It was recently demonstrated in [Chaudhury et al.,Non-Local Euclidean Medians,2012] that the denoising performance of Non-Local Means (NLM) can be improved at large noise levels by replacing the mean by the robust Euclidean median.…

Computer Vision and Pattern Recognition · Computer Science 2016-11-18 Kunal N. Chaudhury , Amit Singer

We propose a randomized version of the non-local means (NLM) algorithm for large-scale image filtering. The new algorithm, called Monte Carlo non-local means (MCNLM), speeds up the classical NLM by computing a small subset of image patch…

Computer Vision and Pattern Recognition · Computer Science 2015-06-18 Stanley H. Chan , Todd Zickler , Yue M. Lu

The efficiency of the Non-Local means (NLM) image denoising algorithm relies on the identification of similar original pixels from noisy similar patches. Hence fine details and low-contrasted structures are badly recovered after the…

Functional Analysis · Mathematics 2013-11-18 Simon Postec , Jacques Froment , Béatrice Vedel
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