Global parametrization of range image sets

We present a method to globally parameterize a surface represented by height maps over a set of planes (range images). In contrast to other parametrization techniques, we do not start with a manifold mesh. The parametrization we compute defines a manifold structure, it is seamless and globally smooth, can be aligned to geometric features and shows good quality in terms of angle and area preservation, comparable to current parametrization techniques for meshes. Computing such global seamless parametrization makes it possible to perform quad remeshing, texture mapping and texture synthesis and many other types of geometry processing operations. Our approach is based on a formulation of the Poisson equation on a manifold structure defined for the surface by the range images. Construction of such global parametrization requires only a way to project surface data onto a set of planes, and can be applied directly to implicit surfaces, nonmanifold surfaces, very large meshes, and collections of range scans. We demonstrate application of our technique to all these geometry types

Rééchantillonnage des nuages de points gigantesques produits lors de la numérisation 3D de monuments

International audienceWe present an original method for resampling point clouds provided by aggregation of LiDAR acquisitions, using a Poisson-disk sampling. It is based on a set of local graphs connected together to get a global representation of the acquired site. This approach allows us to improve the quality of gigantic 3D scans such as the ones generated for cultural heritage preservation, even if the initial volume of data largely exceed the memory capacity of the machine on which those processings are performed.Nous présentons une nouvelle méthode pour rééchantillonner des nuages de points générés par agrégation d'acquisitions LiDAR, à l'aide d'un échantillonnage en disques de Poisson. Celle-ci s'appuie sur un ensemble de graphes locaux représentant la connectivité locale de la surface sous-jacente au nuage, mis en correspondance pour assurer une cohérence globale lors de l'échantillonnage. Cette approche nous permet d'améliorer la qualité des numérisations 3D gigantesques telles que celles produites par les projets de préservation du patrimoine mondial, même si le volume initial des données dépasse très largement la capacité mémoire de la machine sur laquelle ces calculs sont effectués

Quad Meshing

Triangle meshes have been nearly ubiquitous in computer graphics, and a large body of data structures and geometry processing algorithms based on them has been developed in the literature. At the same time, quadrilateral meshes, especially semi-regular ones, have advantages for many applications, and significant progress was made in quadrilateral mesh generation and processing during the last several years. In this State of the Art Report, we discuss the advantages and problems of techniques operating on quadrilateral meshes, including surface analysis and mesh quality, simplification, adaptive refinement, alignment with features, parametrization, and remeshing