PAYAN , Frédéric

the context of this thesis is the rate-distortion optimization for triangular meshes quantized by a geometry coder. Some works consider that geometry is the most important component of polygonal meshes. Geometry coders include a remeshing technique and a wavelet transform providing an efficient multiresolution analysis. The goal of our works is...

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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)...

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We present an efficient compression scheme for animated sequences of triangular meshes of the same connectivity. The proposed algorithm exploits the temporal coherence of the geometry component by using a temporal wavelet filtering. The quantization of the resulting wavelet coefficients is then optimized by a bit allocation process. This...

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In this paper, we propose a powerful bit allocation that optimizes the quantization of the normal mesh geometry. This bit allocation aims to minimize the surface-to-surface distance between the original irregular mesh and the quantized normal one, according to a target bitrate. Moreover, to provide a fast bit allocation, we approximate this...

International audience

sensaas is a tool developed for aligning and comparing molecular shapes and sub-shapes. Alignment is obtained by registration of 3D point-based representations of the van der Waals surface. The method uses local properties of the shape to identify the correspondence relationships between two point clouds containing up to several thousand...

We present an original wavelet-based compression algorithm for sequences of 3D meshes with fixed connectivity. This algorithm, based on a temporal lifting scheme exploits the high temporal coherence of the geometry of successive frames in order to reduce the information needed to represent the original sequence. The resulting sets of wavelet...

Open-source 3D data processing libraries originally developed for computer vision and pattern recognition are used to align and compare molecular shapes and sub-shapes. Here, a shape is represented by a set of points distributed on the van der Waals surface of molecules. Each point is colored by its closest atom, which itself belongs to a user...

In this paper, we propose an efficient low complexity compression scheme for densely sampled irregular 3D meshes. This scheme is based on 3D multiresolution analysis (3D Discrete Wavelet Transform) and includes a model-based bit allocation process across the wavelet subbands. Coordinates of 3D wavelet coefficients are processed separately and...

We propose a new wavelet compression algorithm based on the rate-distortion optimization for densely sampled triangular meshes. Exploiting the normal remesher of Guskov et al., the proposed algorithm includes a wavelet transform and an original bit allocation optimizing the quantization of the wavelet coefficients. The allocation process...

International audience

The objective of this paper is to propose an efficient model-based bit allocation process optimizing the performances of a wavelet coder for semiregular meshes. More precisely, this process should compute the best quantizers for the wavelet coefficient subbands that minimize the reconstructed mean square error for one specific target bitrate....

In this paper, we propose a 3D geometry compression technique for densely sampled surface meshes. Based on a 3D multiresolution analysis (performed by a 3D Discrete Wavelet Transform for semi-regular meshes), this scheme includes a model-based bit allocation process across the wavelet subbands and an efficient surface adapted weighted criterion...

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La similarité entre molécules est un sujet très étudié dans le domaine de la pharmacologie et de la modélisation moléculaire. Jusqu'à présent, bien que présentant de nombreux avantages, les représentations 3D des surfaces moléculaires ont été assez peu employées pour trouver des similarités entre molécules. Dans cette étude, nous montrons qu'il...

SENSAAS is a shape-based alignment software which allows to superimpose molecules. It is based on the publication SenSaaS: Shape-based Alignment by Registration of Colored Point-based Surfaces ( https://doi.org/10.1002/minf.202000081).

La manipulation de données multimédia est souvent lourde et difficile car en dehors du mp3, connu du grand public, les flux de sons, d'images et de vidéos sont très souvent codés avec des fréquences, des codecs, des tailles qui diffèrent énormément selon l'application ou les utilisateurs. L'étude de ces flux et des codecs associés, et leur...

It is well known in wavelet image coding that the biorthogonality of wavelet filters influences the estimation of the Mean Square Error (MSE) due to data quantization. It has been indeed shown that the MSE can be approximated by a weighted MSE with the weights depending on the synthesis filters. These works have been carried on canonical...

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...

We present an original workflow for structuring a point cloud generated from several scans. Our representation is based on a set of local graphs. Each graph is constructed from the depth map provided by each scan. The graphs are then connected together via the overlapping areas, and careful consideration of the redundant points in these regions...