no code implementations • 6 Jul 2023 • Morten Akhøj, James Benn, Erlend Grong, Stefan Sommer, Xavier Pennec
In this paper we demonstrate how sub-Riemannian geometry can be used for manifold learning and surface reconstruction by combining local linear approximations of a point cloud to obtain lower dimensional bundles.
no code implementations • 22 Dec 2021 • Florent Jousse, Xavier Pennec, Hervé Delingette, Matilde Gonzalez
This work addresses the problem of non-rigid registration of 3D scans, which is at the core of shape modeling techniques.
no code implementations • 17 Feb 2021 • Nicolas Guigui, Pamela Moceri, Maxime Sermesant, Xavier Pennec
In cases of pressure or volume overload, probing cardiac function may be difficult because of the interactions between shape and deformations. In this work, we use the LDDMM framework and parallel transport to estimate and reorient deformations of the right ventricle.
1 code implementation • ICLR 2019 • Nina Miolane, Alice Le Brigant, Johan Mathe, Benjamin Hou, Nicolas Guigui, Yann Thanwerdas, Stefan Heyder, Olivier Peltre, Niklas Koep, Hadi Zaatiti, Hatem Hajri, Yann Cabanes, Thomas Gerald, Paul Chauchat, Christian Shewmake, Bernhard Kainz, Claire Donnat, Susan Holmes, Xavier Pennec
We introduce Geomstats, an open-source Python toolbox for computations and statistics on nonlinear manifolds, such as hyperbolic spaces, spaces of symmetric positive definite matrices, Lie groups of transformations, and many more.
1 code implementation • 18 Jun 2019 • Xavier Pennec
For distributions that are highly concentrated around their mean, and for any finite number of samples, we establish explicit Taylor expansions on the first and second moment of the empirical mean thanks to a new Taylor expansion of the Riemannian log-map in affine connection spaces.
Differential Geometry Statistics Theory Statistics Theory
no code implementations • 23 May 2019 • Raphaël Sivera, Hervé Delingette, Marco Lorenzi, Xavier Pennec, Nicholas Ayache
In this study we propose a deformation-based framework to jointly model the influence of aging and Alzheimer's disease (AD) on the brain morphological evolution.
no code implementations • 6 Dec 2018 • Shuman Jia, Antoine Despinasse, ZiHao Wang, Hervé Delingette, Xavier Pennec, Pierre Jaïs, Hubert Cochet, Maxime Sermesant
In this preliminary study, we propose automated, two-stage, three-dimensional U-Nets with convolutional neural network, for the challenging task of left atrial segmentation.
2 code implementations • ICLR 2019 • Nina Miolane, Johan Mathe, Claire Donnat, Mikael Jorda, Xavier Pennec
This paper also presents a review of manifolds in machine learning and an overview of the geomstats package with examples demonstrating its use for efficient and user-friendly Riemannian geometry.
no code implementations • 6 Sep 2016 • Nina Miolane, Susan Holmes, Xavier Pennec
We use tools from geometric statistics to analyze the usual estimation procedure of a template shape.