Search results for "graphics"
showing 10 items of 1223 documents
An Automatic Three-Dimensional Fuzzy Edge Detector
2009
Three-dimensional object analysis is of particular interest in many research fields. In this context, the most common data representation is boundary mesh, namely, 2D surface embedded in 3D space. We will investigate the problem of 3D edge extraction, that is, salient surface regions characterized by high flexure. Our automatic edge detection method assigns a value, proportional to the local bending of the surface, to the elements of the mesh. Moreover, a proper scanning window, centered on each element, is used to discriminate between smooth zones of the surface and its edges. The algorithm does not require input parameters and returns a set of elements that represent the salient features …
Particle Filtering for Tracking in 360 Degrees Videos Using Virtual PTZ Cameras
2019
360 degrees cameras are devices able to record spherical images of the environment. Such images can be used to generate views of the scene by projecting the spherical surface onto planes tangent to the sphere. Each of these views can be considered as the output of a virtual PTZ (vPTZ) camera with specific pan, tilt and zoom parameters. This paper proposes to formulate the visual tracking problem as the one of selecting, at each time, the vPTZ camera to foveate on the target from the unlimited set of simultaneously generated vPTZ camera views. Assuming that the selected vPTZ camera is a stochastic variable, the paper proposes to model the posterior distribution of the underlying stochastic p…
Boolean operations with implicit and parametric representation of primitives using R-functions
2005
We present a new and efficient algorithm to accurately polygonize an implicit surface generated by multiple Boolean operations with globally deformed primitives. Our algorithm is special in the sense that it can be applied to objects with both an implicit and a parametric representation, such as superquadrics, supershapes, and Dupin cyclides. The input is a constructive solid geometry tree (CSG tree) that contains the Boolean operations, the parameters of the primitives, and the global deformations. At each node of the CSG tree, the implicit formulations of the subtrees are used to quickly determine the parts to be transmitted to the parent node, while the primitives' parametric definition …
Multiresolution Analysis for Irregular Meshes
2003
International audience; The concept of multiresolution analysis applied to irregular meshes has become more and more important. Previous contributions proposed a variety of methods using simplification and/or subdivision algorithms to build a mesh pyramid. In this paper, we propose a multiresolution analysis framework for irregular meshes with attributes. Our framework is based on simplification and subdivision algorithms to build a mesh pyramid. We introduce a surface relaxation operator that allows to build a non-uniform subdivision for a low computational cost. Furthermore, we generalize the relaxationoperator to attributes such as color, texture, temperature, etc. The attribute analysis…
Entire reflective object surface structure understanding based on reflection motion estimation
2015
An sub-segmentation method for the reflective surface structure understanding.The use of reflection motion features as spatiotemporal coherence for video segmentation.Straightforward implementation.A building block for object recognition. The presence of reflection on a surface has been a long-standing problem for object recognition since it brings negative effects on object's color, texture and structural information. Because of that, it is not a trivial task to recognize the surface structure affected by the reflection, especially when the object is entirely reflective. Most of the cases, reflection is considered as noise. In this paper, we propose a novel method for entire reflective obj…
Evaluation of the orientation distribution of fibers from reflection images of fibrous samples
2014
We consider illumination systems and mathematical algorithms for determination of the anisotropy and topographical features of an illuminated surface from its reflection images. As a particular example we study determination of the fiber orientation of paper surface. We also consider illumination systems with multiple light sources, and introduce optimization algorithms that exploit different spectral bands of these light sources. We show that a system of three light sources, e.g., a blue, green and red LED placed in a regular triangular form, efficiently prevents distortion of the above features. It is also easy to implement in applications, e.g., of the paper industry. We furthermore show…
Calcul direct d'une tesselation de la surface limite pour les schémas de subdivision uniformes
2017
International audience; Le peu d'utilisation des surfaces de subdivision dans les systèmes CAO est principalement lié au fait que la surface est le plus souvent seulement approchée par des niveaux de raffinement successifs, ce qui induit un manque de pré-cision. De plus, il est difficile d'intégrer la représentation des surfaces de subdivision dans le noyau géométrique (ensemble de primitives et d'outils) des applications CAO. C'est dans ce but que nous décrirons un formalisme général de construction de surfaces de subdivision basé sur les Systèmes Itérés de Fonctions. Le principal apport est que toutes les surfaces de subdivision classiques sont gérées de la même manière quel que soit le s…
La Responsabilidad Social de la Educación Superior como Bien Común. Concepto y desafíos
2018
Este artículo atiende al planteamiento de la Unesco de considerar como bien común a la Educación Superior, en un momento en que las Instituciones de Educación Superior están inmersas en procesos caracterizados por una progresiva mercantilización del conocimiento que condiciona el acceso a la financiación por posicionamiento en rankings internacionales, poniendo en riesgo el objeto de contribuir a un desarrollo sostenible en sus contextos. Mediante un particular análisis de aspectos relacionados con la Responsabilidad Social y la relación con los grupos de interés, se realiza una contribución a la reflexión teórica y a los desafíos para conceptualizar la Educación Superior como un bien común.
Another defence of enumerated types
1991
I claim that enumerations, while of course not strictly necessary, are an elegant and useful facility in modern programming languages. I try to show that arguments recently given against them are weak at best and bogus a t worst, for general-purpose programming. Some related issues on types in programming languages are touched as well. These make it even more questionable whether Oberon marks progress or regress in language design.
Représentation hybride du modèle numérique pour la gestion d'un patrimoine bâti dit ancien
2013
International audience; Ce projet de recherche explore et repousse les limites inhérentes à la représentation numérique du bâti ancien dans la préparation et le suivi de travaux de rénovation. A Cluny, l'Ecole Nationale Supérieure des Arts et Métiers est logée en partie dans les bâtiments de l'ancienne abbaye clunisienne. La représentation numérique d'un bâtiment permet d'archiver la connaissance tout au long de son cycle de vie. L'édifice, datant du XVIIIème siècle, est classé aux monuments historiques. En matière de rénovation les opérations sont strictement encadrées. L'étude de cas portera sur l'isolation intérieure d'un bureau au niveau de la baie ancienne. Elle consiste en l'ajout d'u…