Title
Nonlocal linear minimum mean square error methods for denoising MRI.
Abstract
The presence of noise results in quality deterioration of magnetic resonance (MR) images and thus limits the visual inspection and influence the quantitative measurements from the data. In this work, an efficient two stage linear minimum mean square error (LMMSE) method is proposed for the enhancement of magnitude MR images in which data in the presence of noise follows a Rician distribution. The conventional Rician LMMSE estimator determines a closed-form analytical solution to the aforementioned inverse problem. Even-though computationally efficient, this approach fails to take advantage of data redundancy in the 3D MR data and hence leads to a suboptimal filtering performance. Motivated by this observation, we put forward the concept of nonlocal implementation with LMMSE estimation method. To select appropriate samples for the nonlocal version of the LMMSE estimation, the similarity weights are computed using Euclidean distance between either the gray level values in the spatial domain or the coefficients in the transformed domain. Assuming that the signal dependent component of the noise is optimally suppressed by this filtering and the rest is a white and uncorrelated noise with the image, we adopt a second stage LMMSE filtering in the principal component analysis (PCA) domain to further enhance the image and the noise variance is adaptively adjusted. Experiments on both simulated and real data show that the proposed filters have excellent filtering performance over other state-of-the-art methods. (C) 2015 Elsevier Ltd. All rights reserved.
Year
DOI
Venue
2015
10.1016/j.bspc.2015.04.015
Biomedical Signal Processing and Control
Keywords
Field
DocType
Denoising,Discrete cosine transform,Linear minimum mean square error,Magnetic resonance image,Principal component analysis,Rician distribution
Noise reduction,Pattern recognition,Euclidean distance,Minimum mean square error,Filter (signal processing),Artificial intelligence,Inverse problem,Principal component analysis,Mathematics,Estimator,Rician fading
Journal
Volume
ISSN
Citations 
20
1746-8094
6
PageRank 
References 
Authors
0.40
31
4
Name
Order
Citations
PageRank
P. V. Sudeep1273.44
P. Palanisamy27510.34
Chandrasekharan Kesavadas382.45
Jeny Rajan411318.07