High angular resolution diffusion imaging has become an
important magnetic resonance technique for in vivo imaging.
Most current research in this field focuses on developing
methods for computing the orientation distribution function
(ODF), which is the probability distribution function of water
molecule diffusion along any angle on the sphere. In
this paper, we present a Riemannian framework to carry out
computations on an ODF field. The proposed framework
does not require that the ODFs be represented by any fixed
parameterization, such as a mixture of von Mises-Fisher
distributions or a spherical harmonic expansion. Instead,
we use a non-parametric representation of the ODF, and exploit
the fact that under the square-root re-parameterization,
the space of ODFs forms a Riemannian manifold, namely
the unit Hilbert sphere. Specifically, we use Riemannian
operations to perform various geometric data processing
algorithms, such as interpolation, convolution and linear
and...
Alvina Goh, Christophe Lenglet, Paul M. Thompson,