Noise measurement from magnitude MRI using local estimates of variance and skewness.

TitleNoise measurement from magnitude MRI using local estimates of variance and skewness.
Publication TypeJournal Article
Year of Publication2010
AuthorsJ. Rajan, D. H. J. Poot, J. Juntu, and J. Sijbers
JournalPhysics in medicine and biology
Volume55
Issue16
PaginationN441-9
Date Published2010 Aug 21
ISSN1361-6560
KeywordsAlgorithms, Artifacts, Brain, Data Interpretation, Statistical, Fourier Analysis, Humans, Image Processing, Computer-Assisted, Likelihood Functions, Magnetic Resonance Imaging, Models, Statistical, Myocardium, Normal Distribution, Reproducibility of Results
Abstract

In this note, we address the estimation of the noise level in magnitude magnetic resonance (MR) images in the absence of background data. Most of the methods proposed earlier exploit the Rayleigh distributed background region in MR images to estimate the noise level. These methods, however, cannot be used for images where no background information is available. In this note, we propose two different approaches for noise level estimation in the absence of the image background. The first method is based on the local estimation of the noise variance using maximum likelihood estimation and the second method is based on the local estimation of the skewness of the magnitude data distribution. Experimental results on synthetic and real MR image datasets show that the proposed estimators accurately estimate the noise level in a magnitude MR image, even without background data.

DOI10.1088/0031-9155/55/16/N02
Alternate JournalPhys Med Biol
PubMed ID20679694