نتایج جستجو برای: spherical deconvolution

تعداد نتایج: 54852  

Journal: :Signal Processing 2017
Hang Yang Zhongbo Zhang Yujing Guan

Image deconvolution is still to be a challenging illposed problem for recovering a clear image from a given blurry image, when the point spread function is known. Although competitive deconvolution methods are numerically impressive and approach theoretical limits, they are becoming more complex, making analysis, and implementation difficult. Furthermore, accurate estimation of the regularizati...

2004
A. G. B. M. Saw

A new deconvolution method for Auger electron spectroscopy is presented. This method is based on a non-linear least squares minimizing routine (Levenberg-Marquardt) and global approximation using splines, solving many of the drawbacks inherent to the Van Cittert and Fourier transform based deconvolution methods. The deconvolution routine can be run on a personal computer. The application of thi...

2001
Anthony D. Challinor Daniel J. Mortlock Floor van Leeuwen Anthony N. Lasenby Michael P. Hobson Mark A. J. Ashdown George P. Efstathiou

Despite the fact that the physics of the cosmic microwave background anisotropies is most naturally expressed in Fourier space, pixelised maps are almost always used in the analysis and simulation of microwave data. A complementary approach is investigated here, in which maps are used only in the visualisation of the data, and the temperature anisotropies and polarization are only ever expresse...

Journal: :Medical image analysis 2010
Irina Kezele Maxime Descoteaux Cyril Poupon Fabrice Poupon Jean-Francois Mangin

The choice of local HARDI reconstruction technique is crucial for discerning multiple fiber orientations, which is itself of substantial importance for tractography, and reliable and accurate assessment of white matter fiber geometry. Due to the complexity of the diffusion process and its milieu, distinct diffusion compartments can have different frequency signatures, making the HARDI signal sp...

2012
Christian Baumgartner O. Michailovich J. Levitt O. Pasternak S. Bouix Yogesh Rathi

In this paper, we compare several parametric and non-parametric models of diffusion in a unified framework that allows simultaneous model estimation and tractography. The framework uses the Unscented Kalman Filter (UKF) to compare several variants of spherical harmonics (SH), i.e., SH with sharpening, spherical deconvolution, SH with solid angle and also several parametric models like single an...

2007
LUDOVICO MINATI WŁADYSŁAW P. WĘGLARZ

The foundations and characteristics of models and methods used in diffusion magnetic resonance imaging, with particular reference to in vivo brain imaging, are reviewed. The first section introduces Fick’s laws, propagators, and the relationship between tissue microstructure and the statistical properties of diffusion of water molecules. The second section introduces the diffusion-weighted sign...

2012
Joachim Welker Esther Illek Franz J Giessibl

In frequency-modulation atomic force microscopy the direct observable is the frequency shift of an oscillating cantilever in a force field. This frequency shift is not a direct measure of the actual force, and thus, to obtain the force, deconvolution methods are necessary. Two prominent methods proposed by Sader and Jarvis (Sader-Jarvis method) and Giessibl (matrix method) are investigated with...

2012
Jérémy Schmitt Jean-Luc Starck J. M. Casandjian Jalal M. Fadili I. Grenier J. Schmitt

A multiscale representation-based denoising method for spherical data contaminated with Poisson noise, the multiscale variance stabilizing transform on the sphere (MS-VSTS), has been previously proposed. This paper first extends this MS-VSTS to spherical two and one dimensions data (2D-1D), where the two first dimensions are longitude and latitude, and the third dimension is a meaningful physic...

Journal: :NeuroImage 2008
Jussi Tohka Anthonin Reilhac

In this work, we evaluated three iterative deconvolution algorithms and compared their performance to partial volume (PV) correction based on structural imaging in brain positron emission tomography (PET) using a database of Monte Carlo-simulated images. We limited our interest to quantitative radioligand PET imaging, particularly to (11)C-Raclopride and striatal imaging. The studied deconvolut...

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