In this work, we first propose an original and efficient computational framework to model continuous diffusion MRI (dMRI) signals and analytically recover important diffusion features such as the Ensemble Average Propagator (EAP) and the Orientation Distribution Function (ODF). Then, we develop an efficient parametric dictionary learning algorithm and exploit the sparse property of a well-desig...

White matter fiber clustering aims to get insight about anatomical structures in order to generate atlases, perform clear visualizations, and compute statistics across subjects, all important and current neuroimaging problems. In this work, we present a diffusion maps clustering method applied to diffusion MRI in order to segment complex white matter fiber bundles. It is well known that diffusi...

One of the major goals of the NIH Blueprint Human Connectome Project was to map and quantify the white matter connections in the brain using diffusion tractography. Given the prevalence of complex white matter structures, the capability of resolving local white matter geometries with multiple crossings in the diffusion magnetic resonance imaging (dMRI) data is critical. Increasing b-value has b...

High angular resolution diffusion imaging (HARDI) has opened up new perspectives for the delineation of crossing and branching fiber pathways by orientation distribution function (ODF). The fiber orientations contained in an imaging voxel are the key factor in tractography. To extract real fiber orientations from ODF, a hybrid method is proposed for computing the principal directions of ODF by ...

We propose a regularized, fast, and robust analytical solution for the Q-ball imaging (QBI) reconstruction of the orientation distribution function (ODF) together with its detailed validation and a discussion on its benefits over the state-of-the-art. Our analytical solution is achieved by modeling the raw high angular resolution diffusion imaging signal with a spherical harmonic basis that inc...

INTRODUCTION MR tractography methods depend on the accurate estimation of orientation distribution functions (ODFs) from diffusion MRI data. A new ODF estimation method called the Funk-Radon and Cosine Transform (FRACT) was recently introduced for this purpose [1]. The FRACT is a linear method that generalizes the previous Funk-Radon Transform (FRT) [2]. While the FRACT is as easy to characteri...

At the High Energy X-ray laboratory (HEX-lab, Department of Engineering Science, University of Oxford, UK) we carry out studies of deformation and structure of engineering materials and components. Laboratory and synchrotron X-ray beams provide the principal means of analysis and measurement. A variety of other techniques are also in use. We present a range of applications and case studies in h...

The crimp of the text ile fibers is very crit ical to determine its properties and volumin isity. The microscopic characteristic of the nonwoven fabric is totally depends on the linearity and length of the crimp and the amplitude of the crimp. In this review paper we have discussed about the crimp calculat ion, measurement techniques and the standards used for the text ile nonwoven substrates. ...

The di usion orientation distribution function (ODF) can be reconstructed from q-ball imaging (QBI) to map the complex intravoxel structure of water di usion. As acquisition time is particularly large for high angular resolution di usion imaging (HARDI), fast estimation algorithms have recently been proposed, as an on-line feedback on the reconstruction accuracy. Thus the acquisition could be s...

In diffusion MRI (dMRI) domain, many High Angular Resolution Diffusion Imaging (HARDI) methods were proposed to estimate Ensemble Average Propagator (EAP) and Orientation Distribution Function (ODF). They normally need many samples, which limits their applications. Some Compressive Sensing (CS) based methods were proposed to estimate ODF in Q-Ball Imaging (QBI) from limited samples. However EAP...