Title
Efficient and robust nonlocal means denoising of MR data based on salient features matching.
Abstract
The nonlocal means (NLM) filter has become a popular approach for denoising medical images due to its excellent performance. However, its heavy computational load has been an important shortcoming preventing its use. NLM works by averaging pixels in nonlocal vicinities, weighting them depending on their similarity with the pixel of interest. This similarity is assessed based on the squared difference between corresponding pixels inside local patches centered at the locations compared. Our proposal is to reduce the computational load of this comparison by checking only a subset of salient features associated to the pixels, which suffice to estimate the actual difference as computed in the original NLM approach. The speedup achieved with respect to the original implementation is over one order of magnitude, and, when compared to more recent NLM improvements for MRI denoising, our method is nearly twice as fast. At the same time, we evidence from both synthetic and in vivo experiments that computing of appropriate salient features make the estimation of NLM weights more robust to noise. Consequently, we are able to improve the outcomes achieved with recent state of the art techniques for a wide range of realistic Signal-to-Noise ratio scenarios like diffusion MRI. Finally, the statistical characterization of the features computed allows to get rid of some of the heuristics commonly used for parameter tuning.
Year
DOI
Venue
2012
10.1016/j.cmpb.2011.07.014
Computer Methods and Programs in Biomedicine
Keywords
Field
DocType
nonlocal vicinity,mri denoising,appropriate salient feature,computational load,nlm weight,diffusion mri,mr data,heavy computational load,original nlm approach,recent nlm improvement,robust nonlocal,actual difference,magnetic resonance imaging,diagnostic imaging,algorithms
Noise reduction,Computer vision,Weighting,Square (algebra),Computer science,Medical imaging,Heuristics,Artificial intelligence,Pixel,Speedup,Salient
Journal
Volume
Issue
ISSN
105
2
1872-7565
Citations 
PageRank 
References 
17
0.93
23
Authors
4
Name
Order
Citations
PageRank
Antonio Tristan-Vega118716.88
Verónica García-Pérez2221.81
Santiago Aja-Fernández337831.66
Carl-fredrik Westin42040173.83