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Julien Dardenne
PhD from INSA Lyon in Images & Systems
Teacher at University of Lyon

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Thesis

J. Dardenne, S. Valette, N. Siauve and R. Prost, 3D Mesh Generation of Anatomical Structures for Electromagnetic and Thermal Simulations, Ph.D. in computer science, Institut National des Sciences Appliquees, November 2009. [Pdf]

International journals

J. Dardenne, S. Valette, N. Siauve and R. Prost,Variational tetraedral mesh generation from discrete volume data, The Visual Computer (proceedings of CGI 2009), Volume 25, no. 5, pages 401-410, May 2009. [Preprint]

Abstract In this paper, we propose a novel tetrahedral mesh generation algorithm, which takes volumic data (voxels) as an input. Our algorithm performs a clustering of the original voxels within a variational framework. A vertex replaces each cluster and the set of created vertices is triangulated in order to obtain a tetrahedral mesh, taking into account both the accuracy of the representation and the elements quality. The resulting meshes exhibit good elements quality with respect to minimal dihedral angle and tetrahedra form factor. Experimental results show that the generated meshes are well suited for Finite Element Simulations.

J. Dardenne, S. Valette, N. Siauve and R. Prost, Modélisation adaptative 3D de structures anatomiques pour la simulation électromagnétique et thermique. European Journal of Electrical Engineering, pp in press, 2009.

Abstract In this paper, we propose a new method for generate anatomical meshes by tetrahedral elements with the aim of simulating the phenomena resulting from a voluntary or involuntary exposure of the human body at waves radio frequencies. This mesh will be used to resolve, by the finite element method, the equations of Maxwell, for the electromagnetic part and the equation of Pennes for thermal part. we propose a novel tetrahedral mesh generation algorithm, which takes volumic data (voxels) as an input.

S. Nicolas, J. Dardenne, T. Paquet and L. Heutte, Utilisation de modèles markoviens 2D pour la segmentation d'images de documents, revue I3, 2009. [Preprint]

Abstract In this work we are interested in image analysis thanks to the use of Markovian generative and discriminative models : Hidden Markov Random Fields and Conditional Random Fields. We present a 2D implementation of conditional random fields which have been used mainly for on dimensional data until now. The proposed approach is based on a discriminative classifiers combination scheme. We illustrate and compare the performance of this approach with Hidden Markov random fields through its application to document structure analysis of complex degraded Handwritten Documents : Flaubert's manuscripts.

International conferences with proceedings

J. Dardenne, N. Siauve, S. Valette, R. Prost and N. Burais, Impact of Tetrahedral Mesh Quality for Electromagnetic and Thermal Simulations, In proceedings of the 17th Conference on the Computation of Electromagnetic Fields , COMPUMAG'09, Florianopolis, Brazil, pages in-press, November 2009. [PDF]

Abstract : Finite element simulation can be directly affected by mesh quality. The accuracy of finite element calculations is dependent upon of the mesh quality. Previously, we have introduced a novel approach to the construction of high-quality, isotropic tetrahedral meshes from segmented medical imaging data. This article proposes an experimental evaluation of the impact of our tetrahedral meshes on electromagnetic and thermal simulations with finite elements.

J. Dardenne, S. Valette, N. Siauve, B. Khaddour and R. Prost, Exploiting Curvature to compute the Medial Axis with Constrained Centroidal Voronoi Diagram On Discrete Data, In IEEE International Conference on Image Processing , ICIP'09, Cairo, Egypt, November 2009.

Abstract : In this paper, we present a novel method for medial axis approximation based on Constrained Centroidal Voronoi Diagram of discrete data (image, volume). The proposed approach is based on the shape boundary subsampling controled by a clustering approach which generates a Voronoi Diagram well suited for Medial Axis extraction. The resulting Voronoi Diagram is further filtered in order to capture the correct topology of the medial axis. The main contribution of this paper is the integration of both a curvature maps and a distance map for controlling the local variability of Voronoi cells densities. Examples of complex shape processing prove the effectiveness of the proposed approach.

J. Dardenne, S. Valette, N. Siauve and R. Prost, Medial Axis Approximation with Constrained Centroidal Voronoi Diagrams On Discrete Data, Computer Graphics International 2008, Istanbul, Turkey. [PDF]

Abstract : In this paper, we present a novel method for medial axis approximation based on Constrained Centroidal Voronoi Diagram of discrete data (image, volume). The proposed approach is based on the shape boundary subsampling by a clustering approach which generates a Voronoi Diagram well suited for Medial Axis extraction. The resulting Voronoi Diagram is further filtered so as to capture the correct topology of the medial axis. The resulting medial axis appears largely invariant with respect to typical noise conditions in the discrete data. The method is tested on various synthetic as well as real images. We also show an application of the approximate medial axis to the sizing field for triangular and tetrahedral meshing.

S. Nicolas, J. Dardenne, T. Paquet and L. Heutte, Document Image Segmentation Using a 2D Conditionnal Random Field Model, ICDAR 2007, Curitiba, Brazil. [PDF]

Abstract : This work relates to the implementation of a 2D conditional random field model in the context of document image analysis. Our model makes it possible to take variability into account and to integrate contextual knowledge, while taking benefit from machine learning techniques. Experiments on handwritten drafts of Flaubert show that these models provide interesting solutions.

National conferences with proceedings

J. Dardenne, S. Valette, N. Siauve and R. Prost, Génération de maillages triangulaires adaptatifs 2d avec des diagrammes de voronoï centroïdaux, colloque Gretsi, 2009, Dijon, France.

Abstract : In this paper, we consider the problem of triangular mesh generation from a binary image with respect to density function of triangles. This problem is relevant for the numerical simulation of physical phenomena by the finite element method. The triangulation has to respect the geometry of the various regions constituting the image. The shape and size of triangular elements have an impact on the results accuracy. We propose a 2D triangular mesh generation algorithm which adapts itself to the objects boundaries in the image.

J. Dardenne, S. Valette, N. Siauve and R. Prost, Approximation de l'axe médian pour les objets discrets avec prise en compte de la courbure, colloque Gretsi, 2009, Dijon, France.

Abstract : In this article, we consider the problem of the medial axis approximation from a discrete object (image or volume). The proposed approach is based on the shape boundary subsampling by a clustering approach which generates a Voronoi Diagram well suited for Medial Axis extraction. The resulting Voronoi Diagram is further filtered so as to capture the correct topology of the medial axis. The method is tested on various synthetic as well as real images. The resulting medial axis appears largely invariant with respect to typical noise conditions in the discrete data.

J. Dardenne, Génération de maillages tétraédriques adaptatifs de structure anatomique du corps humain pour la simulation électromagnétique et thermique, colloque JCGE'2008, Décembre 2008, Lyon, France. Prix JCGE'08. [PDF]

Résumé : Dans cet article, nous présentons une nouvelle méthode de création de structures anatomiques maillées par des tétraèdres dans le but de simuler les phénomènes résultant d'une exposition volontaire ou involontaire du corps humain à des ondes radiofréquences. Cette représentation maillée sera utilisée pour résoudre, par la méthode des éléments finis, les équations de Maxwell, pour la partie électromagnétique, et l'équation de Pennes pour la partie thermique. Nous proposons une nouvelle méthode, rapide et robuste, de construction du maillage à partir d'un ensemble de voxels. La représentation maillée devra avoir des caractéristiques adaptées à la résolution, par la méthode des éléments finis, des phénomènes étudiés. Les caractéristiques importantes sont: le respect de la géométrie des organes du corps humain, la forme et la taille des éléments tétraédriques qui ont une incidence sur la précision du résultat.

S. Nicolas, J. Dardenne, T. Paquet and L. Heutte, Un modèle de champ aléatoire conditionnel 2D appliqué à la segmentation d'images de documents, RFIA'2008, 22-25 janvier 2008, Amiens, France. Prix AFRIF 2008 de la meilleure communication RF. [PDF]

Abstract : This work relates to the implementation of a 2D conditional random field model in the context of document image analysis. Our model makes it possible to take variability into account and to integrate contextual knowledge, while taking benefit from machine learning techniques. Experiments on handwritten drafts of Flaubert show that these models provide interesting solutions.


Reports


- Master's thesis IGIS
- Master's defense

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