0000000000105250
AUTHOR
Olivier Aubreton
showing 29 related works from this author
A coarse to fine 3D acquisition system
2015
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
2016
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…
Rétine Vidéo Rapide Réalisée en Technologie CMOS
2008
Nous présentons une rétine réalisée en technologie CMOS 0.6 μm dédiée à l’observation de phénomènes lumineux rapides. Le pixel que nous avons conçu est basé sur un principe de modulation de la durée d’une impulsion représentative du flux lumineux incident. Ce pixel a été validé par simulation SPICE grâce aux bibliothèques AMS du fondeur puis dessiné en full- custom de façon à optimiser sa surface, on a obtenu ainsi un pixel dont la dimension est de 49.2μm de coté avec un taux de remplissage de 18 %.
A 3D Scanner for Transparent Glass
2009
Many practical tasks in industry, such as automatic inspection or robot vision, often require the scanning of three-dimensional shapes by use of non-contact techniques. However, few methods have been proposed to measure three-dimensional shapes of transparent objects because of the difficulty of dealing with transparency and specularity of the surface. This paper presents a 3D scanner for transparent glass objects based on Scanning From Heating (SFH), a new method that makes use of local surface heating and thermal imaging.
3D reconstruction of external and internal surfaces of transparent objects from polarization state of highlights
2014
A vision-based method is proposed to measure the 3D shape of external and internal surfaces (not accessible) of smooth transparent objects. Looking at the reflections of point sources on a specular surface with a polarimetric camera, we combine the measurements of two techniques: shape from distortion and shape from polarization. It permits us to recover the position and orientation of the specular surface for each detected point. The internal surface of transparent objects exhibiting as well a specular component, the same technique is used on the highlights coming from the back surface, taking into account the refraction by using polarimetric ray tracing.
Real time polarization imaging of weld pool surface
2015
The search for an efficient on-line monitoring system focused on the real-time analysis of arc welding quality is an active area of research. The topography and the superficial temperature field of the weld pool can provide important information which can be used to regulate the welding parameters for depositing consistent welds. One difficulty relies on accessing this information despite the bright dazzling welding arc. In the present work, Stokes polarimetry and associated shape-from-polarization methods are applied for the analysis of the weld pool through its 810 nm-wavelength infrared emissions. The obtained information can provide a better understanding of the process, such as the usa…
Weld pool surface temperature measurement from polarization state of thermal emission
2014
This paper presents a passive polarimetry method using a division of aperture optical device in order to measure the temperature distribution at the weld pool surface. Thermal emission from a hot liquid metal was investigated at a near-infrared wavelength corresponding to a blind spectral window of a helium plasma generated during gas tungsten arc welding process. The refractive index of liquid metal and the surface radiance are deduced from the polarisation state of thermal emissions. Based upon the knowledge of both characteristics, the temperature distribution can be calculated. Conseil Régional de Bourgogne
A Continuous Time Pattern Recognition Retina
2002
International audience; We present in this paper a pattern recognition retina operating in continuous time. During a programming phase, the reference image is acquired by the sensor. After thresholding, the resulting binary image is stored in the sensor's pixels. During the recognition phase, the retina calculates, in an analog way and in continuous time, the zero displacement intercorrelation of the current image with the binary reference image and its complement. These two intercorrelation values are output as currents. By comparing these currents to expected values, determined during the programming phase, a shift of the pattern or a difference between the observed and programmed pattern…
A Correlation Retina in Standard 0.6um : Application in Positioning System
2003
International audience; We have designed and fabricated a programmable retina that is capable of recognizing patterns stored in memory in real-time. Each of the pixels of the retina is composed of a photodiode and an electronic device used during the programming phase to digitize the image of the pattern to recognize into a binary image stored in latches. The array of pixels is thus partitioned into two complementary disjoint sub-sets with all the photodiodes of the same sub-set connected together in order to obtain the sum total of the currents. During the analysis phase, an optical correlation between the projected image and the reference binary image memorized in the circuit is done. The…
Coarse to fine : toward an intelligent 3D acquisition system
2015
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…
“Scanning from Heating” and “Shape from Fluorescence”
2011
3D surface acquisition is a subject which has been studied to a large extent. A significant number of techniques for acquiring shape have been proposed, and a wide range of commercial solutions are available. Nevertheless, today’s systems still have difficulties when digitizing objects with non-Lambertian surfaces in the visible light spectrum, as is the case of transparent, semi-transparent or highly reflective materials (e.g. glass, crystals, some plastics and shiny metals). In this chapter, some of the issues of traditional scanning systems are addressed by considering various approaches using the radioactive properties of materials, the polarization information of the reflected light as…
Hardware Computation of Moment Functions in a Silicon Retina Using Binary Patterns
2006
International audience; We present in this paper a method for implementing moment functions in a CMOS retina for shape recognition applications. The method is based on the use of binary patterns and it allows the computation of different moment functions such geometric and Zernike moments of any orders by an adequate choice of the binary patterns. The advantages of the method over other methods described in the literature is that it is particularly suitable for the design of a programmable retina circuit where moment functions of different orders are obtained by simply loading the correct binary patterns into the memory devices implemented on the circuit. The moment values computed by the m…
Playfully Coding
2017
This paper describes a framework for successful interaction between universities and schools. It is common for computing academics interested in outreach (computer science evangelism) to work with local schools, particularly in countries where the computing curriculum in K-12 is new or underdeveloped. However it is rare for these collaborations to be ongoing, and for resources created through these school-university links to be shared beyond the immediate neighborhood. We have achieved this, through shared resources, careful evaluation, and cross-country collaboration. The activities themselves are inspired by ideas from the Lifelong Kindergarten group at MIT, emphasizing playful exploratio…
Thermal camera calibration with cooled down chessboard
2019
International audience; Calibration of a camera have various applications in computer vision. This process is particularly challenging with a thermal camera instead of a standard color one. A calibration target with two layers of different thermal emissivity is commonly used but reflects appear and degrade the corner extraction of the chessboard. While traditional and commonly used methods heat the target chessboard, we cool it down that inverts the distribution of emission of the two layers. The reflects on the reflective layer enhance the contrast instead of decreasing it. Experiments on various configurations and orientations demonstrate the superiority of the proposed method.
3D shape extraction of internal and external surfaces of glass objects
2013
Three-dimensional (3D) digitization of manufactured objects has been investigated for several years and consequently, many techniques have been proposed. Even if some techniques have been successfully commercialized, most of them assume a diffuse or near diffuse reflectance of the object’s surface, and difficulties remain for the acquisition of “optically non cooperative” surfaces, such as transparent or specular ones. To address such surfaces, we propose a non conventional technique, called “Scanning from Heating” (SfH). In contrast to classical active triangulation techniques that acquire the reflection of visible light, we measure the thermal emission of the heated surface. The aim of th…
Characterizing weld pool surfaces from polarization state of thermal emissions
2013
International audience; In this Letter, a vision-based remote sensing methodology is proposed to measure the topography of weld pool surfaces from one single view. Thermal radiations emitted by the hot liquid metal at a wavelength within the arc plasma blind spectral window are acquired by a wavefront division polarimetric system. The refractive index of the liquid metal and the topography of the weld pool surface are inferred from the polarimetric state of the thermal radiations.
A combined three-dimensional digitisation and subsurface defect detection data using active infrared thermography
2016
International audience; In recent years, NonDestructive Testing (NDT) systems have been upgraded with three-dimensional information. Indeed, combine the three-dimensional and thermal information allows a more meaningful analysis. In the literature, the data for NDT and three-dimensional (3D) reconstruction analysis are commonly acquired from independent systems. However, the use of two such systems leads to error analysis during the data registration. In an attempt to overcome such problems, we propose a single system based on active thermography approach using heat point-source stimulation to get the 3D digitization as well as subsurface defect detection. The experiments are conducted on s…
Masquer l'Objet pour Mieux le Reconnaître
2005
National audience; L’évolution des technologies de pointe a repoussé les limites des domaines d’application de l’imagerie numérique de sorte que les capteurs d’images sont aujourd’hui omniprésents dans beau- coup d’applications, que ce soit des applications scientifiques ou des appli- cations liées au divertissement et à un usage grand public. Ces capteurs four- nissent en général une image qui est par la suite traitée par un ordinateur ou des circuits électroniques spécialisés. La course vers la miniaturisation et vers des systèmes autonomes compacts et légers nécessite aujourd’hui des cap- teurs d’images de plus en plus petits et de faible consommation. De plus, il existe des applications…
Scanning from heating: 3D shape estimation of transparent objects from local surface heating.
2009
Today, with quality becoming increasingly important, each product requires three-dimensional in-line quality control. On the other hand, the 3D reconstruction of transparent objects is a very difficult problem in computer vision due to transparency and specularity of the surface. This paper proposes a new method, called Scanning From Heating (SFH), to determine the surface shape of transparent objects using laser surface heating and thermal imaging. Furthermore, the application to transparent glass is discussed and results on different surface shapes are presented.
Special Section Guest Editorial: Quality Control by Artificial Vision VI
2020
This guest editorial introduces the Special Section on Quality Control by Artificial Vision VI.
Attitude measurement by artificial vision
2005
The recent development of light and low-cost airborne platforms (microlight, drones, kites, balloons,...) has led to the need for simple and low-cost devices allowing attitude measurement with respect to a reference horizon of the platform itself or of an embedded setting. A theoretical study of the conditions for measuring attitude angles from artificial vision is proposed and an original practical algorithm allowing these measurements to be performed in real time is described. An implementation in a CMOS retina circuit is also presented. These points are illustrated by experiments confirming the feasibility of the device.
Numérisation 3D de surfaces métalliques spéculaires et diffuses par imagerie infrarouge active
2012
National audience; Depuis plus de 20 ans, le besoin en numérisation 3D de pièces industrielles augmente considérablement. Par conséquent, un grand nombre de techniques expérimentales ont été proposées ainsi que quelques solutions commerciales. Cependant, des difficultés subsistent pour l'acquisition de surfaces optiquement noncoopératives, comme les surfaces transparentes et/ou spéculaires. En effet, la transmission, réfraction ou réflexion spéculaire de la lumière va à l'encontre du fonctionnement des systèmes conventionnels d'acquisition 3D, qui repose sur l'aspect diffus de la réflexion. Un moyen de contourner ce problème est le dépôt d'une couche de poudre matifiante afin de rendre la s…
Primitives extraction based on structured-light images
2013
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.
Extraction de primitives à partir d'images de lumière structurée
2013
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…
Scanning From Heating : extension pour la numérisation 3D de surfaces métalliques spéculaires
2011
National audience; En raison des difficultés liées à la réflexion spéculaire de certaines surfaces, peu de méthodes répétables ont été proposées pour mesurer la forme en trois dimensions des objets métalliques polis. Nous présentons l'application sur ce type de matériau d'une nouvelle approche appelée " Scanning From Heating ". Cette méthode a été initialement développée pour la numérisation 3D d'objets transparents. Du fait des nombreuses différences de propriétés physiques entre métaux et diélectriques, le principe de fonctionnement de la méthode SFH doit être modifié. Une simulation des échanges thermique grâce à un logiciel de calcul par éléments finis a permis de déterminer comment ada…
Application du Scanning From Heating à la numérisation 3D de surfaces métalliques spéculaires
2011
Because of the difficulty of dealing with specularity of several surfaces, few methods have been proposed to measure three-dimensional shapes of specular metallic objects. In this paper we present an application on this kind of material of an approach called "Scanning From Heating". This approach has been developed initially for 3D reconstruction of transparent objects. This article presents an application of the working principle of SFH method on material with high thermal conductivity and low absorptivity.
Estimation de surface de Bézier à partir d'images de lumière structurée dans une optique de compression
2013
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.
Scanning From Heating: 3D Shape Estimation of Transparent Objects from Local Surface Heating
2009
International audience
3D Scanning of specular and diffuse metallic surfaces using an infrared technique
2012
International audience; For the past two decades, the need for 3D Scanning of industrial objects has increased significantly. Therefore, many experimental techniques and commercial solutions have been proposed. However, difficulties remain for the acquisition of optically non-cooperative surfaces, such as transparent or specular surfaces. To address highly reflective metallic surfaces, we propose the extension of a technique that was originally dedicated to glass objects. In contrast to conventional active triangulation techniques that measure the reflection of visible radiation, we measure the thermal emission of a surface, which is locally heated by a laser source. Considering the thermop…