0000000000004892
AUTHOR
Céline Roudet
showing 16 related works from this author
From A Medial Surface To A Mesh
2012
Medial surfaces are well-known and interesting surface skeletons. As such, they can describe the topology and the geometry of a 3D closed object. The link between an object and its medial surface is also intuitively understood by people. We want to exploit such skeletons to use them in applications like shape creation and shape deformation. For this purpose, we need to define medial surfaces as Shape Representation Models (SRMs). One of the very first task of a SRM is to offer a visualization of the shape it describes. However, achieving this with a medial surface remains a challenging problem. In this paper, we propose a method to build a mesh that approximates an object only described by …
Mesh connectivity compression using convection reconstruction
2007
International audience; During a highly productive period running from 1995 to about 2002, the research in lossless compression of 3D meshes mainly consisted in a hard battle for the best bitrates. But for a few years, compression rates seem stabilized around 1.5 bit per vertex for the connectivity coding of usual meshes, and more and more work is dedicated to remeshing, lossy compression, or gigantic mesh compression, where memory and CPU optimizations are the new priority. However, the size of 3D models keeps growing, and many application fields keep requiring lossless compression. In this paper, we present a new contribution for single-rate lossless connectivity compression, which first …
Semi-Regular Triangle Remeshing: A Comprehensive Study
2014
Semi-regular triangle remeshing algorithms convert irregular surface meshes into semi-regular ones. Especially in the field of computer graphics, semi-regularity is an interesting property because it makes meshes highly suitable for multi-resolution analysis. In this paper, we survey the numerous remeshing algorithms that have been developed over the past two decades. We propose different classifications to give new and comprehensible insights into both existing methods and issues. We describe how considerable obstacles have already been overcome, and discuss promising perspectives.
Toward a real-time tracking of dense point-sampled geometry
2012
4 pages; International audience; In this paper, we address the problem of tracking temporal deformations between two arbitrary densely sampled point-based surfaces. We propose an intuitive and efficient resolution to the point matching problem within two frames of a sequence. The proposed method utilizes two distinct space partition trees, one for each point cloud, which both are defined on a unique discrete space. Our method takes advantage of multi-resolution concerns, voxel adjacency relations, and a specific distance function. Experimental results obtained from both simulated and real reconstructed data sets demonstrate that the proposed method can handle efficiently the tracking proces…
Bords d'une surface médiane : Identifications et applications
2014
National audience; Un squelette d'une forme fermée est une structure mince, centrée dans cette forme, décrivant sa topologie et sa géométrie. Les squelettes permettent de développer des applications interactives en synthèse d'images~: l'utilisateur peut manipuler intuitivement des formes en modifiant leurs squelettes. Parmi toutes les formulations de squelettes, nous nous intéressons en particulier à la surface médiane. Ses éléments, nommés atomes, sont les sphères maximales intérieures à la forme décrite. Les positions des atomes sont organisées en courbes et surfaces, qui composent la structure squelettale. Cette structure peut être d'une grande aide pour manipuler une forme. Cependant, e…
Study and Comparison of Surface Roughness Measurements
2014
Journées du Groupe de Travail en Modélisation Géométrique (GTMG'14), Lyon; This survey paper focus on recent researches whose goal is to optimize treatments on 3D meshes, thanks to a study of their surface features, and more precisely their roughness and saliency. Applications like watermarking or lossy compression can benefit from a precise roughness detection, to better hide the watermarks or quantize coarsely these areas, without altering visually the shape. Despite investigations on scale dependence leading to multi-scale approaches, an accurate roughness or pattern characterization is still lacking, but challenging for those treatments. We think there is still room for investigations t…
Méthodes de contrôle de la rugosité à partir des propriétés différentiels de courbes autosimilaires.
2023
La rugosité a de nombreuses applications, l’industrie l’utilise comme outil pour avoir des propriétés de surface recherchés ou pour le contrôle qualité, le domaine de l’informatique graphique s’intéresse à la synthétiser pour la génération de terrains ou la génération de textures et aussi à simuler ses effets sur la lumière avec les BRDF. . . Dans cette présentation, nous proposeronsun rappel sur la rugosité, notamment sa définition plus précise que "surface ou courbe non lisse" et ses outils de quantification suivi d’une comparaison de certaines de ses méthodes de génération, illustrant l’intérêt d’une approche fractale pour l’étudier. Nous commencerons par des méthodes simples mais offran…
Adaptive surface compression with geometric wavelets.
2008
The recent advances in computer graphics and digitization allow access to an ever finer three-dimensional modelling of the world. The critical challenges with 3D models lie in their transmission and rendering, which must fit the heterogeneity of the end resources (network bandwidth, display terminals . . . ). In this context, this thesis investigates the progressive compression and transmission of 3D models, based on multiresolution analysis, to provide a scalable representation of these geometric models. This work is part of "CoSurf", a collaborative research project involving LIRIS laboratory and France Télécom R&D in Rennes. The proposed hierarchical compression method is based on a wave…
Semi-Regular Triangle Remeshing: A Comprehensive Study
2016
International audience; Semi-regular triangle remeshing algorithms convert irregular surface meshes into semi-regular ones. Especially in the field of computer graphics, semi-regularity is an interesting property because it makes meshes highly suitable for multiresolution analysis. In this paper, we survey the numerous remeshing algorithms that have been developed over the past two decades. We propose different classifications to give new and comprehensible insights into both existing methods and issues. We describe how considerable obstacles have already been overcome, and discuss promising perspectives.
Differential constraints for iteratively generated curves
2021
Roughness is a complex concept, that is multiscale, and based on the study of the local behavior of a curve or a surface in a given neighborhood. A large number of conventional statistical parameters are currently available to attempt to appreciate this concept in the different application areas that make use of it. But it is often difficult, for a given application domain or a special need, to know precisely which parameter(s) connect(s) the topography of a surface to the physical phenomena that it undergoes. We believe that a geometric characterization should be more suitable. We suggest to control roughness by exploiting the differential behavior of curves and surfaces. We are interested…
A Study on Patch-Based Progressive Coding Schemes of Semi-Regular 3D Meshes for Local Wavelet Compression and View-Dependent Transmission
2010
International audience; This paper firstly introduces a wavelet-based segmentation for three-dimensional (3D) Semi-Regular (SR) meshes, as a pre-processing step, in a region-independent progressive coding algorithm. The proposed segmentation process aims at producing homogeneous regions with respect to their frequency amplitudes on the mesh surface, in other words: patches with different degrees of roughness. We have then studied the behavior of the wavelets, obtained during the independent coding of each region, especially close to the patch boundaries. The main contribution of this paper consists in considering three different possible wavelet decompositions, close to the region borders, …
Remaillage semi-régulier pour les maillages surfaciques triangulaires : un état de l'art
2010
National audience; Les maillages surfaciques triangulaires sont désormais couramment utilisés pour modéliser des formes tridimensionnelles. Beaucoup de ces modèles géométriques sont obtenus à partir de techniques de numérisation scanner ou de représentations implicites (isosurfaces). Ainsi la géométrie de ces maillages est souvent très dense (sur-échantillonnage) et leur connectivité arbitraire (irrégularité du voisinage des sommets). Il est alors souvent nécessaire de les remailler afin de réduire leur complexité (simplification), améliorer la qualité des triangles produits, optimiser l'échantillonnage de la géométrie ou encore rendre la connectivité la plus régulière possible. Concernant …
Skeleton-Based Multiview Reconstruction
2016
International audience; The advantage of skeleton-based 3D reconstruction is to completely generate a single 3D object from well chosen views. Having numerous views is necessary for a reliable reconstruction but projections of skeletons lead to different topologies. We reconstruct 3D objects with curved medial axis (whose topology is a tree) from the perspective skeletons on an arbitrary number of calibrated acquisitions. The main contribution is to estimate the 3D skeleton, from multiple images: its topology is chosen as the closest to those of the perspective skeletons on the set of images, which means that the number of topology changes to map the 3D skeleton topology to topologies on im…
Représentation, analyse et caractérisation de surfaces rugueuses
2020
Nous présentons un projet de recherche dans lequel, nous proposons d’aborder la problématique de la représentation numérique, de l’analyse et de la caractérisation de surfaces rugueuses. La rugosité est un concept complexe, par nature multi-échelle et reposant sur l’étude du comportement local d’une surface dans un voisinage donné. Son évaluation sur les surfaces est essentielle pour de nombreux problèmes expérimentaux. Cela explique les nombreuses études réalisées dans les domaines applicatifs liés à la physique et la mécanique, là où le contrôle et la maîtrise de l’état des surfaces constituent un besoin majeur pour les industriels. Un grand nombre de paramètres conventionnels normalisés …
La rugosité des surfaces et ses applications
2022
Dans cet article, nous présentons un état de l'art sur les applications liées à la notion de rugosité des surfaces. Ce travail ne prétend pas être exhaustif. Nous nous sommes attachés à référencer les travaux dans les domaines qui nous ont paru les plus pertinents. Le monde industriel s'intéresse depuis longtemps à caractériser et à contrôler la rugosité pour la conception, la fabrication et le contrôle qualité. En informatique graphique, la rugosité est modélisée pour produire des géométries de surfaces ou pour simuler son impact sur la lumière lors du processus de rendu.
Surface canal, squelette et espace des sphères
2016
A canal surface is the envelope of a one-parameter familly of oriented spheres. With the knowledge of center an radius functions associated to it, it is easy to compute a parametrisation of the surface. In this article, we study the inverse operation, which is the search for the spheres in the canal surface. By selecting a point on the boundary and using the sphere space, we estimate the maximal sphere tangent with this point and a second point on the boundary. Furthermore, we estimate a second sphere, which allows to build the characteiristic circle of the canal surface. So this article consists in a new approach of the skeletonization of an object. Indeed, a skeleton is a shape representa…