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Phys Med Biol. 2010 Aug 21;55(16):N441-9. doi: 10.1088/0031-9155/55/16/N02. Epub 2010 Aug 3.

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

Author information

1
Vision Lab, Department of Physics, University of Antwerp, Belgium. jeny.rajan@ua.ac.be

Erratum in

  • Phys Med Biol. 2010 Nov 21;55(22):6973.

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.

PMID:
20679694
DOI:
10.1088/0031-9155/55/16/N02
[Indexed for MEDLINE]

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