Дисертації з теми "Fusion géométrique"
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Tusa, jumbo Eduardo Alejandro. "Apport de la fusion LiDAR - hyperspectral pour la caractérisation géométrique et radiométrique des arbres." Thesis, Université Grenoble Alpes, 2020. https://tel.archives-ouvertes.fr/tel-03212453.
Mountain forests provide environmental ecosystem services (EES) to communities: supplying of recreational landscapes, protection against natural hazards, supporting biodiversity conservation, among others. The preservation of these EES through space and time requires a good characterization of the resources. Especially in mountains, stands are very heterogeneous and timber harvesting is economically possible thanks to trees of higher value. This is why we want to be able to map each tree and estimate its characteristics, including quality, which is related to its shape and growth conditions. Field inventories are not able to provide a wall to wall cover of detailed tree-level information on a large scale. On the other hand, remote sensing tools seem to be a promising technology because of the time efficient and the affordable costs for studying forest areas. LiDAR data provide detailed information from the vertical distribution and location of the trees, but it is limited for mapping species. Hyperspectral data are associated to absorption features in the canopy reflectance spectrum, but is not effective for characterizing tree geometry. Hyperspectral and LiDAR systems provide independent and complementary data that are relevant for the assessment of biophysical and biochemical attributes of forest areas. This PhD thesis deals with the fusion of LiDAR and hyperspectral data to characterize individual forest trees. The leading idea is to improve methods to derive forest information at tree-level by extracting geometric and radiometric features. The contributions of this research work relies on: i) an updated review of data fusion methods of LiDAR and hyperspectral data for forest monitoring, ii) an improved 3D segmentation algorithm for delineating individual tree crowns based on Adaptive Mean Shift (AMS3D) and an ellipsoid crown shape model, iii) a criterion for feature selection based on random forests score, $5$-fold cross validation and a cumulative error function for forest tree species classification. The two main methods used to derive forest information at tree level are tested with remote sensing data acquired in the French Alps
Godineau, Kévin. "Optimisation du pilotage de chaînes opto-mécaniques pour l'exécution de trajectoires en fabrication additive par fusion laser sur lit de poudre." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN019.
In metal additive manufacturing by laser powder bed fusion, the geometry and mechanical characteristics of the produced parts are generated during the manufacturing process. These two aspects are greatly influenced by the laser spot trajectories, and by the control of the energy provided to the powder locally. The numerical control system, whose purpose is to generate instructions to be sent to actuators, has therefore a significant impact on the quality of the parts produced.This work proposes to study the local impact of the operations carried out in the numerical control on both the trajectories executed and the energy provided to the material. In the literature, few studies have addressed these aspects in additive manufacturing. For this reason, an experimental platform is implemented and used to analyze and better understand the operations currently implemented in industrial numerical controls.First, a mathematical model representative of the machine geometry is established. This model converts the laser spot trajectories into instructions for actuators. The model developed is used to improve the calibration step of the machines. Once the system is calibrated, the instructions sent to the actuators are studied. The various processes carried out in the industrial numerical control are analysed, limitations are highlighted and several proposals for improvements are implemented. All these developments are then used to precisely control the energy supplied to the material in the case of certain trajectories adapted to the process. The scientific developments proposed in these works are all validated experimentally on an additive manufacturing machine or on the test bench developed. The work carried out makes it possible to envisage many perspectives concerning the improvement of the treatments carried out inside the numerical control in additive manufacturing
Hils, Martin. "Fusion libre et autres constructions génériques." Phd thesis, Université Paris-Diderot - Paris VII, 2006. http://tel.archives-ouvertes.fr/tel-00274128.
la fusion libre sur une fusion fortement minimale est effectuée. Puis, des variations sur le thème de la fusion sont étudiées (courbe générique et structures bicolores). À titre d'exemple, il suit des résultats que l'on peut donner un sens à la notion d'une courbe générique dans un corps pseudofini. Enfin, l'axiomatisabilité de l'automorphisme générique est démontrée dans certains contextes issus d'une amalgamation à la Hrushovski dont la fusion libre et les théories des différents corps bicolores de Poizat (noir, rouge et vert).
Cherif, Mohamed Abderrazak. "Alignement et fusion de cartes géospatiales multimodales hétérogènes." Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5002.
The surge in data across diverse fields presents an essential need for advanced techniques to merge and interpret this information. With a special emphasis on compiling geospatial data, this integration is crucial for unlocking new insights from geographic data, enhancing our ability to map and analyze trends that span across different locations and environments with more authenticity and reliability. Existing techniques have made progress in addressing data fusion; however, challenges persist in fusing and harmonizing data from different sources, scales, and modalities.This research presents a comprehensive investigation into the challenges and solutions in vector map alignment and fusion, focusing on developing methods that enhance the precision and usability of geospatial data. We explored and developed three distinct methodologies for polygonal vector map alignment: ProximityAlign, which excels in precision within urban layouts but faces computational challenges; the Optical Flow Deep Learning-Based Alignment, noted for its efficiency and adaptability; and the Epipolar Geometry-Based Alignment, effective in data-rich contexts but sensitive to data quality. Additionally, our study delved into linear feature map alignment, emphasizing the importance of precise alignment and feature attribute transfer, pointing towards the development of richer, more informative geospatial databases by adapting the ProximityAlign approach for linear features like fault traces and road networks. The fusion aspect of our research introduced a sophisticated pipeline to merge polygonal geometries relying on space partitioning, non-convex optimization of graph data structure, and geometrical operations to produce a reliable fused map that harmonizes input vector maps, maintaining their geometric and topological integrity.In practice, the developed framework has the potential to improve the quality and usability of integrated geospatial data, benefiting various applications such as urban planning, environmental monitoring, and disaster management. This study not only advances theoretical understanding in the field but also provides a solid foundation for practical applications in managing and interpreting large-scale geospatial datasets
Albinet, C. "Sensibilité des observables radars à la variabilité temporelle et à la configuration géométrique de forêts tempérées et tropicales à partir de mesure de proximité haute-résolution. Extension à la simulation dans la perspective de fusion de données radar-o." Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-01068830.
Mélou, Jean. "Fusion d'approches photométriques et géométriques pour la création de modèles 3D." Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0030.
Practical solutions for 3D-reconstruction from photographs are generally based on multi-view methods (called geometric methods) that only very partially use the photometric information contained in the images. The use of the latter should increase the fineness of the reconstructed relief and allow the estimate of the photometric characteristics of the scene, i.e. surface reflectance and incident lighting. This thesis shows how an approach combining multiview and photometric techniques can effectively improve a 3D-reconstruction pipeline. We start by presenting a way to make the shape-from-shading method operational in daylight conditions. This allows us to combine multiview and photometric approaches in the form of a variational problem, for which we propose a numerical solving scheme. However, like shape-from-shading itself, the proposed method requires an a priori knowledge of reflectance and lighting. We present a method for the joint estimation of both these quantities from a coarse relief of the scene. As a conclusion, we present an algorithm which, from the images used by a multi-view 3D-reconstruction pipeline, allows us to estimate a reflectance map and a depth map per view, as well as the lighting of the scene
Helbert, David. "Système partagé de fusion : d'un prétraitement des informations à une reconstruction dynamique." Poitiers, 2005. http://www.theses.fr/2005POIT2343.
This thesis has been made in the frame of a DGA/CNRS allocation in collaboration with the SIC laboratory, university of Poitiers, and Géographie, Image et Perception department, Centre d'Expertise Parisien (Délégation Générale pour l'Armement). These works are coming within the framework of dynamical image processing including pre-processing, information fusion and 3D reconstruction. In the first time, we have been interested by a multiresolution decomposition, named ridgelet transform, allowing to represent efficiently linear singularities in an image. We propose to discretize this transform using discrete analytical objects in the theoritical frame of the discrete geometry. The resulting transform is named 3D Discrete Analytical Ridgelet Transform. Performances of this method and its local extension are illustrated by image sequences denoising from application frame of this thesis, but also by colour image restoration. In a second time, we have worked in the only application frame of sportive gesture dynamical analysis to propose a 3D reconstruction method of marker trajectories fixed on athletes. The gesture is then recorded by several cameras. The principle is to apply tracking algorithms on markers extracted from each image sequences, then to use the set of data to reconstruct athlete movements in the 3D space. The tracking algorithm uses the formalism of evidence theory allowing to represent both a partial knowledge and an ignorance and to combine uncertain data
Diop, Adama. "Détermination expérimentale et numérique de la propagation du front de fusion d'un mélange binaire : géométrie cylindrique avec transferts pariétaux." Paris 12, 1998. http://www.theses.fr/1998PA12A028.
Scotto, d'Abusco Manuel. "Modélisation numérique du transport turbulent cœur-bord dans un tokamak en géométrie réaliste par une méthode numérique avancée." Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0173.
Nowadays a challenge remains the design of optimized plasma scenarios for tokamak operation to control the heat flow from the core region to the wall. This calls for the development of efficient and reliable numerical codes with predictive capabilities for plasma simulations. The present work aims to develop a high-order finite elements code based on hybrid discontinuous Galerkin numerical scheme and an efficient implicit time integration method for solving non isothermal Braginskii reduced fluid equations in versatile tokamak and magnetic equilibrium geometries. The use of such numerical scheme allows to perform simulations with time evolving magnetic configurations, avoiding expensive re-meshing of the computational domain. The structure and the realization of such a numerical tool is presented. The feasibility of the latter is then investigated through a careful validation and benchmarking operation with SolEdge3X. Self-consistent sources of particle, due to plasma recycling, and energy due to Ohmic heating are introduced to perform 2D simulation of a full poloidal tokamak cross section. With such a model the main features of a detached plasma are investigated for the WEST tokamak machine. The first core-edge transport simulations of an entire WEST discharge (shot #54487) are shown from the start-up phase to the final plasma landing. Comparisons between experimental interferometry and synthetic simulation data show a remarkable agreement. The time evolution of the particles and heat fluxes at the wall, are analyzed and exploited to assess the tungsten sputtering, using both a simple cinematic model and the impurity tracker monte-carlo code ERO2.0
Laribi, Elias. "Modélisation numérique de l'impact de la géométrie magnétique sur le plasma de bord des tokamaks." Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0298.
This phD work has shown that, in a limiter configuration, the elongation of magnetic surfaces has a stabilizing effect with respect to the edge plasma turbulence. This leads to a reduction of the edge plasma width when the elongation increases. Regarding triangularity, this phD work revealed that its effects on the edge plasma were weaker than those of elongation. A better understanding of these trends has been possible thanks to a theoretical work on a simplified interchange model. This work has also revealed the importance of the magnetic field spatial variability on the poloidal size of turbulent structures and therefore on the radial turbulent fluxes. In a second step, the study of a divertor configuration with one X point has shown that the the magnetic field spatial variability was so important that it could be one of the reasons that explain the enhancement of the low field side ballooned nature of edge plasma turbulence in a divertor geometry. Still concerning the divertor geometry, this phD also revealed that the internal material receives more heat compared to the external material when the toroidal magnetic field is oriented in the direct direction (= magnetic drift of the ions pointing towards the X point). A possible explanation of this observation is the existence of a significant plasma circulation from the low field side to the high field side at the X point that we observed in this configuration. Finally, we were able to confirm that one way to improve this heat flux distribution on the walls was to merge two X points perfectly (= ideal snowflake proposed in 2007 by Ryutov and Sukhanovsky)
Le, Guen Emilie. "Etude du procédé de soudage hybride laser/MAG : Caractérisation de la géométrie et de l'hydrodynamique du bain de fusion et développement d'un modèle 3D thermique." Phd thesis, Université de Bretagne Sud, 2010. http://tel.archives-ouvertes.fr/tel-00546986.
Le, Guen Émilie. "Étude du procédé de soudage hybride laser/MAG : caractérisation de la géométrie et de l’hydrodynamique du bain de fusion et développement d’un modèle 3D thermique." Lorient, 2010. https://tel.archives-ouvertes.fr/tel-00546986.
Hybrid laser/MIG-MAG welding shows high advantages compared to laser welding or GMAW arc welding used separately. Thanks to this process, higher productivity can be gained through higher welding speed, higher squeeze tolerance moreover possible improvement of the metallurgical properties of the weld seam can be obtained. However, many operating parameters have to be set up in order to achieve optimal process. The complex physical phenomena, which govern welding process, have to be understood in order to use efficiently this technique in mass production. Understanding of these phenomena is also necessary to program numerical simulations which fit to this process. In the first step, experimental studies have been carried out with GMAW, laser and hybrid welding on samples of S355 steel. Influence of operating parameters has been analyzed through films performed with speed camera and macrographies of weld seam cross section. Surface deformations of the melt pool, induced by the arc pressure, weld pool length, droplet detachment and welding speed, have been analyzed precisely from images of the surface melt pool. In a second step, a numerical model was developed using the COMSOL Multiphysics® software for MAG, laser and hybrid laser/MAG welding processes. A 3D quasi-stationary model has been calculated from the temperature field within the metal. The originality of the MAG and hybrid model lies in the prediction of the melt pool surface profile used to determine the 3D geometry, by taking into account the material input The influence of different parameters such as arc power and speed welding on the efficiency as well as the distribution radius of the arc power and the arc pressure are analyzed through validations with different experimental results and different calculation configurations
Mehmood, Muhammad Owais. "Détection de personnes pour des systèmes de videosurveillance multi-caméra intelligents." Thesis, Ecole centrale de Lille, 2015. http://www.theses.fr/2015ECLI0016/document.
People detection is a well-studied open challenge in the field of Computer Vision with applications such as in the visual surveillance systems. Monocular detectors have limited ability to handle occlusion, clutter, scale, density. Ubiquitous presence of cameras and computational resources fuel the development of multi-camera detection systems. In this thesis, we study the multi-camera people detection; specifically, the use of multi-view probabilistic occupancy maps based on the camera calibration. Occupancy maps allow multi-view geometric fusion of several camera views. Detection with such maps create several false detections and we study this phenomenon: ghost pruning. Further, we propose two novel techniques in order to improve multi-view detection based on: (a) kernel deconvolution, and (b) occupancy shape modeling. We perform non-temporal, multi-view reasoning in occupancy maps to recover accurate positions of people in challenging conditions such as of occlusion, clutter, lighting, and camera variations. We show improvements in people detections across three challenging datasets for visual surveillance including comparison with state-of-the-art techniques. We show the application of this work in exigent transportation scenarios i.e. people detection for surveillance at a train station and at an airport
Lecrosnier, Louis. "Estimation de pose multimodale- Approche robuste par les droites 2D et 3D." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR089.
Camera pose estimation consists in determining the position and the orientation of a camera with respect to a reference frame. In the context of mobile robotics, multimodality, i.e. the use of various sensor types, is often a requirement to solve complex tasks. However, knowing the orientation and position, i.e. the pose, of each sensor regarding a common frame is generally necessary to benefit multimodality. In this context, we present two major contributions with this PhD thesis. First, we introduce a pose estimation algorithm relying on 2D and 3D line and a known vertical direction. Secondly, we present two outliers rejection and line pairing methods based on the well known RANSAC algorithm. Our methods make use of the vertical direction to reduce the number of lines required to 2 and 1, i.e. RANSAC2 and RANSAC1. A robustness evaluation of our contributions is performed on simulated and real data. We show state of the art results
Didier, Pascal. "Propriétés optiques de marqueurs fluorescents d'intérêt biologique en interaction avec leur environnement : étude par spectroscopie femtoseconde." Phd thesis, Université Louis Pasteur - Strasbourg I, 2004. http://tel.archives-ouvertes.fr/tel-00008127.
Castagnas, Luce. "De la synergie des images satellitaires SPOT/ERS au travers de deux exemples de fusion." Phd thesis, 1995. http://pastel.archives-ouvertes.fr/pastel-00979324.