نتایج جستجو برای: inhomogeneity correction

تعداد نتایج: 170481  

2007
Wen-Hung Chao Chien-Wen Cho Yen-Yu Shih You-Yin Chen Chen Chang

A new method for enhancing the contrast of magnetic resonance images (MRI) by retinex algorithm is proposed. It can correct the blurrings in deep anatomical structures and inhomogeneity of MRI. Multiscale retinex (MSR) employed SSR with different weightings to correct inhomogeneities and enhance the contrast of MR images. The method was assessed by applying it to phantom and animal images acqui...

Journal: :Magnetic resonance in medicine 2015
Dongyeob Han Yoonho Nam Sung-Min Gho Dong-Hyun Kim

PURPOSE To introduce macroscopic B0 field inhomogeneity-compensated volumetric R2 * mapping method with a three-dimensional (3D) z-shim multi-echo acquisition. METHODS The proposed z-shim sequence acquired conventional and z-shimmed echoes alternately with bipolar readout gradients. A constant-valued z-shim gradient was applied prior to each negative readout gradient lobe. A phase combination...

2015
Chencheng Huang Li Zeng

Intensity inhomogeneity causes many difficulties in image segmentation and the understanding of magnetic resonance (MR) images. Bias correction is an important method for addressing the intensity inhomogeneity of MR images before quantitative analysis. In this paper, a modified model is developed for segmenting images with intensity inhomogeneity and estimating the bias field simultaneously. In...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2012
Han Wang Christof Schütte Pingwen Zhang

In the present paper, we develop an accurate error estimate of the nonbonded short-range interactions for the inhomogeneous molecular systems. The root-mean-square force error is proved to be decomposed into three additive parts: the homogeneity error, the inhomogeneity error, and the correlation error. The magnitude of the inhomogeneity error, which is dominant in the interfacial regions, can ...

2012
M. Renugadevi Deepa Varghese V. Vaithiyanathan N. Raju

Medical image fusion and segmentation has high impact on the digital image processing due to its spatial resolution enhancement and image sharpening. It has been used to derive useful information from the medical image data that provides the most accurate and robust method for diagnosis. This process is a compelling challenge due to the presence of inhomogeneities in the intensity of images. Fo...

Journal: :NeuroImage 2009
Jorge Jovicich Silvester Czanner Xiao Han David H. Salat André J. W. van der Kouwe Brian T. Quinn Jennifer L. Pacheco Marilyn S. Albert Ronald J. Killiany Deborah Blacker R. Paul Maguire H. Diana Rosas Nikos Makris Randy L. Gollub Anders M. Dale Bradford C. Dickerson Bruce Fischl

Automated MRI-derived measurements of in-vivo human brain volumes provide novel insights into normal and abnormal neuroanatomy, but little is known about measurement reliability. Here we assess the impact of image acquisition variables (scan session, MRI sequence, scanner upgrade, vendor and field strengths), FreeSurfer segmentation pre-processing variables (image averaging, B1 field inhomogene...

Journal: :NeuroImage 2006
Alex D Leow Andrea D Klunder Clifford R Jack Arthur W Toga Anders M Dale Matt A Bernstein Paula J Britson Jeffrey L Gunter Chadwick P Ward Jennifer L Whitwell Bret J Borowski Adam S Fleisher Nick C Fox Danielle Harvey John Kornak Norbert Schuff Colin Studholme Gene E Alexander Michael W Weiner Paul M Thompson

Measures of brain change can be computed from sequential MRI scans, providing valuable information on disease progression, e.g., for patient monitoring and drug trials. Tensor-based morphometry (TBM) creates maps of these brain changes, visualizing the 3D profile and rates of tissue growth or atrophy, but its sensitivity depends on the contrast and geometric stability of the images. As part of ...

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