Concept

Sphère

Publications associées (170)

Stereographic Wavelet Frames on the Sphere

Pierre Vandergheynst, Laurent Jacques, Iva Bogdanova Vandergheynst

In this paper we exploit the Continuous Wavelet Transform (CWT) on the two dimensional sphere, introduced previously by two of us, to build associated Discrete Wavelet Frames. We first explore half-continuous frames, i.e., frames where the position remains ...

2005

On the behavior of spherical and non-spherical grain assemblies, its modeling and numerical simulation

Lionel Pournin

This thesis deals with the numerical modeling and simulation of granular media with large populations of non-spherical particles. Granular media are highly pervasive in nature and play an important role in technology. They are present in fields as diverse ...

EPFL2005

Surface Nanostructuring through block copolymer self-assembly

Jürgen Brugger, Sivashankar Krishnamoorthy, Harry Heinzelmann, Raphaël Pugin

Synthesis of nanostructures using polymer self-assembly methods have gained widespread attention due to the multitude of possibilities they offer and their simple and cost-effective approaches. Self-assembly of block copolymers has been recognized as a pro ...

2005

Direct observation of nondiffusive motion of a Brownian particle

László Forró, Andrzej Kulik, Sylvia Jeney, Branimir Lukic

The thermal position fluctuations of a single micron-sized sphere immersed in a fluid were recorded by optical trapping interferometry with nanometer spatial and microsecond temporal resolution. We find, in accord with the theory of Brownian motion includi ...

2005

Laplacian Operator, Diffusion Flow and Active Contour on non-Euclidean Images

Jean-Philippe Thiran, Pierre Vandergheynst, Xavier Bresson, Iva Bogdanova Vandergheynst

We propose here some basic approaches to direct processing of the

360^o

-images as we take into consideration the geometry of each one. Obviously, the geometry of each of these images is a consequence of the geometry of the sensor's mirror used. This tech ...

2005

A biomechanics-based articulation model for medical applications

Anderson Maciel

Computer Graphics came into the medical world especially after the arrival of 3D medical imaging. Computer Graphics techniques are already integrated in the diagnosis procedure by means of the visual tridimensional analysis of computer tomography, magnetic ...

EPFL2005

Correspondence principle between spherical and Euclidean wavelets

Pierre Vandergheynst, Yves Wiaux, Laurent Jacques

Wavelets on the sphere are reintroduced and further developed independently of the original group theoretic formalism, in an equivalent, but more straightforward approach. These developments are motivated by the interest of the scale-space analysis of the ...

2005

Acquiring, structuring shapes and annotating them with semantics to improve design activities

Daniel Thalmann, Frédéric Vexo

Shapes incorporate geometry as well as semantics and can be defined in 2D, 3D or higher dimensions. Geometric models can be structured in such a way that they can provide a relevant framework to insert semantic information or view dependent information abo ...

2005

Progressive coding of 3D objects based on overcomplete decompositions

Pascal Frossard, Pierre Vandergheynst, Ivana Tosic

This paper presents a progressive coding scheme for 3D objects, based on an overcomplete decomposition of the 3D model on a sphere. Due to increased freedom in the bases construction, redundant expansions have shown interesting approximation properties in ...

2005

Hydrogel Microspheres: Influence of Chemical Composition on Surface Morphology, Local Elastic Properties, and Bulk Mechanical Characteristics

Andrzej Kulik, Jutta Christine Wandrey

Hydrogel microspheres, beads, and capsules of uniform size, differing in their chem. compn., have been prepd. by electrostatic complex formation of sodium alginate with divalent cations and polycations. These have served as model spheres to study the influ ...

2004

Graph Chatbot

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.

Connectez-vous pour utiliser Chat avec Graph Search

Laplacian Operator, Diffusion Flow and Active Contour on non-Euclidean Images

Jean-Philippe Thiran, Pierre Vandergheynst, Xavier Bresson, Iva Bogdanova Vandergheynst

We propose here some basic approaches to direct processing of the

360^o

-images as we take into consideration the geometry of each one. Obviously, the geometry of each of these images is a consequence of the geometry of the sensor's mirror used. This tech ...

2005