0000000000201085
AUTHOR
Vincent Daval
Primitives extraction based on structured-light images
International audience; Geometric attributes such as curvature or surface orientation are additional information of the 3D points obtained after the scanning of an object. In the classic 3D chain, characterized by a sequential structure, these information are determined from the dense point cloud (from a 3D scanner). Then, they are used to reduce the amount of information and allows to obtain a simplified model. In this paper, we investigate the possibility to extract some geometric attributes, directly from 2D images obtained by the camera of a structured-light system.
A coarse to fine 3D acquisition system
International audience; The 3D chain (acquisition-processing-compression) is , most of the time , sequenced into several steps. Such approaches result into an one-dense acquisition of 3D points. In large scope of applications , the first processing step consists in simplifying the data. In this paper , we propose a coarse to fine acquisition system which permits to obtain simplified data directly from the acquisition. By calculating some complementary information from 2D images , such as 3D normals , multiple homogeneous regions will be segmented and affected to a given primitive class. Contrary to other studies , the whole process is not based on a mesh. The obtained model is simplified di…
Wood fiber orientation assessment based on punctual laser beam excitation: A preliminary study
International audience; The EU imposes standards for the use of wood in structural applications. Local singularities such as knots affect the wood mechanical properties. They can be revealed by looking at the wood fiber orientation. For this reason, many methods were proposed to estimate the orientation of wood fiber using optical means, X-rays, or scattering measurement techniques. In this paper, an approach to assess the wood fiber orientation based on thermal ellipsometry is developed. The wood part is punctually heated with a Nd-YAG Laser and the thermal response is acquired by an infrared camera. The thermal response is elliptical due to the propagation of the heat through and along th…
Extraction de primitives à partir d'images de lumière structurée
National audience; Les attributs géométriques tels que la courbure ou la normale constituent des informations complémentaires aux points 3D obtenus suite à la numérisation d'une surface ou d'un objet. Dans la chaine 3D classique, présentant une structure séquentielle, ces informations sont déterminées à partir du nuage de points dense (issus par exemple d'un scanner 3D). Par la suite, elles sont utilisées pour diminuer la quantité d'information et permettre ainsi d'aboutir à un modèle simplifié (compressé ou modélisé sous forme de primitives). Dans cet article, nous nous intéressons à la possibilité d'extraire certains des attributs mentionnés plus haut, directement à partir des images 2D o…
Coarse to fine : toward an intelligent 3D acquisition system
International audience; The 3D acquisition-compression-processing chain is , most of the time , sequenced into independent stages. As resulting , a large amount of 3D points are acquired whatever the geometry of the object and the processing to be done in further steps. It appears , particularly in mechanical part 3D modeling and in CAD , that the acquisition of such an amount of data is not always mandatory. We propose a method aiming at minimizing the number of 3D points to be acquired with respect to the local geometry of the part and therefore to compress the cloud of points during the acquisition stage. The method we propose is based on a new coarse to fine approach in which from a coa…
Estimation de surface de Bézier à partir d'images de lumière structurée dans une optique de compression
National audience; Compression of 3D datas has become a topic of increasing importance over the evolution of scanners. With evolution of technologies, the commercial scanners give more and more data points, which can lead to difficulties in transmission or storage. In most cases, the acquisition does not take into account the final use of the data. While in many cases, this would limit the number of points. In this paper, we propose an approach which simplifies the scatterplot for industrial purposes using Bezier surfaces.
Automatic measurement of wood fiber orientation and knot detection using an optical system based on heating conduction.
In this paper, a new approach to computing the deviation of wood grain is proposed. To do this, the thermal conduction properties of timber are used (higher conduction in the fiber direction). Exciting the surface of the wood with a laser and capturing the thermal conduction using a thermal camera, an ellipse can be observed. Using a method similar to the tracheid effect, it is possible to extract information from this ellipse, such as the slope of grain and the presence of knots. With this method it is therefore possible to extend the mechanical model (assessing the mechanical properties of timber) to take certain singularities into account. Using this approach, the slope of grain can be e…