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Schertzer, Jérémie. "Exploiting modern GPUs architecture for real-time rendering of massive line sets". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAT037.
Pełny tekst źródłaIn this thesis, we consider massive line sets generated from brain tractograms. They describe neural connections that are represented with millions of poly-line fibers, summing up to billions of segments. Thanks to the two-staged mesh shader pipeline, we build a tractogram renderer surpassing state-of-the-art performances by two orders of magnitude.Our performances come from fiblets: a compressed representation of segment blocks. By combining temporal coherence and morphological dilation on the z-buffer, we define a fast occlusion culling test for fiblets. Thanks to our heavily-optimized parallel decompression algorithm, surviving fiblets are swiftly synthesized to poly-lines. We also showcase how our fiblet pipeline speeds-up advanced tractogram interaction features.For the general case of line rendering, we propose morphological marching: a screen-space technique rendering custom-width tubes from the thin rasterized lines of the G-buffer. By approximating a tube as the union of spheres densely distributed along its axes, each sphere shading each pixel is retrieved relying on a multi-pass neighborhood propagation filter. Accelerated by the compute pipeline, we reach real-time performances for the rendering of depth-dependant wide lines.To conclude our work, we implement a virtual reality prototype combining fiblets and morphological marching. It makes possible for the first time the immersive visualization of huge tractograms with fast shading of thick fibers, thus paving the way for diverse perspectives
Tobor, Ireneusz. "Utilisation des surfels dans le rendu des surfaces 3D". Bordeaux 1, 2002. http://www.theses.fr/2002BOR12640.
Pełny tekst źródłaLegland, David. "Morphométrie de structures cellulaires biologiques partiellement observées par imagerie 3D". Paris 5, 2005. http://www.theses.fr/2005PA05S039.
Pełny tekst źródłaThis work presents methods to characterize morphology of 3D cellular structures partially observed by discrete images, as well as their application to morphometric description of tomato pericarp. An estimation method of geometric properties of a material was developed, in the particular case where the sampling probability of pixels is not uniform inside the image. The principle is to express locally the morphological parameters of the structure, and te weight each contribution by the inverse of its sampling probability. We present also the computation of sampling prohabilities in 3D images acquired perpendicularly to a smooth surface, based on simple regularity assumptions. In order te compare the quality of information obtained with 2D and 3D images, the estimation of surface density in vertical sections was applied to discrete images. Finally we present an integramed approach to characterize a cellular material, the tomato pericarp. This approach comprises the acquisition of images using confocal microscopy, image processing to segment biological cells, and the application of estimators we developed. We could characterize the morphologv of tomato pericarp cells globally and as a function of depth in the pericarp
Lee, Jinho. "Synthesis and analysis of human faces using multi-view, multi-illumination image ensembles". Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133366279.
Pełny tekst źródłaBosnjak, Seminario Antonio. "Segmentation et modélisation dynamiques : application à la reconstruction 3D d'images échocardiographiques". Rennes 1, 2003. http://www.theses.fr/2003REN10018.
Pełny tekst źródłaAl, Moussawi Ali. "Reconstruction 3D de vaisseaux sanguins". Electronic Thesis or Diss., Toulon, 2014. http://www.theses.fr/2014TOUL0014.
Pełny tekst źródłaThis work concerns the 3D reconstruction of blood vessels from a limited number of 2D transversal cuts obtained from scanners. If data are missing, a coherentreconstruction with a vessel network is obtained. This approach allows to limit human interventions in processing images of 2D transversal cuts. Knowing that the images used are obtained by scanner, the difficulty is to connect the blood vessels between some widely spaced cuts in order to produce the graph corresponding to the network of vessels. We identify the vessels on each trnasversal cut as a mass to be transported, we construct a graph solution of a branched transport problem. At this stage, we are able to reconstruct the 3D geometry by using the 2D Level Set Functions given by the transversal cuts and the graph information. The 3D geometry of blood vessels is represented by the data of the Level Set function defined at any point of the space whose 0-level corresponds to the vessel walls. The resulting geometry is usually integrated in a fluid mechanic code solving the incompressible Navier-Stokes equations on a Cartesian grid strictly included in a reconstructed geometry. The inadequacy of the mesh with the interface of the geometry is overcomed thanks to a modified boundary condition leading to an accurate computation of the constraints to the walls
Deschamps, Thomas. "Extraction de Courbes et Surfaces par Methodes de Chemins Minimaux et Ensembles de Niveaux. Applications en Imagerie Medicale 3D". Phd thesis, Université Paris Dauphine - Paris IX, 2001. http://tel.archives-ouvertes.fr/tel-00003335.
Pełny tekst źródłaDeschamps, Thomas. "Extractions de courbes et surfaces par méthodes de chemins minimaux et ensembles de niveaux : applications en imagerie médicale 3D". Paris 9, 2001. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=2001PA090038.
Pełny tekst źródłaIn this thesis, we focus on the use of minimal path techniques and Level-Sets active contours, for curve and shape extraction in 3D medical images. In the first part of thesis, we worked upon the reduction of the computing cost for path extraction. We proposed several path extraction algorithms for 2D as well as for 3D images. And we applied those techniques to real medical imaging problems, in particular automatic path extraction for virtual endoscopy and interactive and real-time path extraction with on-the-fly training. In the second part, we focused on surface extraction. We developed a fast algorithm for pre-segmentation, on the basis of the minimal path formalism of the first part. We designed a collaborative method between this algorithm and a Level-Sets formulation of the problem, which advantage is to be able to handle any topological change of the surfaces segmented. This method was tested on different segmentation problems, such as brain aneurysms and colon polyps, where target is accuracy of the segmentation, and enhanced visualization of the pathologies. In the last part of the thesis, we mixed results from previous part to design a specific method for tubular shape description and segmentation, where description is the extraction of the underlying skeleton of our objects. The skeletons are trajectories inside our objects, which are used as well for virtual inspection of pathologies, as for accurate definition of cross-sections of our tubular objects. In the last chapter we show applications of our algorithms to the extraction of branching structures. We study the vascular tree extraction in contrast enhanced medical images, and we apply the same principle to the more complex problem of the bronchial tree extraction in multi-slice CT scanners of the lungs
Al, Moussawi Ali. "Reconstruction 3D de vaisseaux sanguins". Thesis, Toulon, 2014. http://www.theses.fr/2014TOUL0014/document.
Pełny tekst źródłaThis work concerns the 3D reconstruction of blood vessels from a limited number of 2D transversal cuts obtained from scanners. If data are missing, a coherentreconstruction with a vessel network is obtained. This approach allows to limit human interventions in processing images of 2D transversal cuts. Knowing that the images used are obtained by scanner, the difficulty is to connect the blood vessels between some widely spaced cuts in order to produce the graph corresponding to the network of vessels. We identify the vessels on each trnasversal cut as a mass to be transported, we construct a graph solution of a branched transport problem. At this stage, we are able to reconstruct the 3D geometry by using the 2D Level Set Functions given by the transversal cuts and the graph information. The 3D geometry of blood vessels is represented by the data of the Level Set function defined at any point of the space whose 0-level corresponds to the vessel walls. The resulting geometry is usually integrated in a fluid mechanic code solving the incompressible Navier-Stokes equations on a Cartesian grid strictly included in a reconstructed geometry. The inadequacy of the mesh with the interface of the geometry is overcomed thanks to a modified boundary condition leading to an accurate computation of the constraints to the walls
Abrishami-Moghaddam, Hamid. "Segmentation d'images multidimensionnelles d'IRM cardiaque pour l'étude du comportement dynamique et la reconstruction 3D du cœur". Compiègne, 1998. http://www.theses.fr/1998COMP1107.
Pełny tekst źródłaDominio, Fabio. "Real-time hand gesture recognition exploiting multiple 2D and 3D cues". Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424298.
Pełny tekst źródłaLa recente introduzione di applicazioni 3D e monitor stereoscopici ha creato la necessità di nuove interfacce uomo-macchina. I classici dispositivi di input, come la tastiera e il mouse, non sono in grado di sfruttare appieno il potenziale di queste interfacce e non offrono un'interazione naturale. I gesti, invece, forniscono un modo più naturale e sicuro di interagire con computer e altre macchine senza doverle toccare. I campi d'applicazione per le interfacce basate sui gesti spaziano dai videogiochi al riconoscimento automatico del linguaggio dei segni, all'assistenza sanitaria, alla robotica e all'automatizzazione dei veicoli. Il riconoscimento automatico dei segni è un problema impegnativo che sta interessando la comunità scientifica da diversi anni grazie alla sua applicabilità alle interfacce naturali. I primi metodi, basati sul riconoscimento a partire da immagini o video, erano affetti dai tipici problemi che caratterizzano questo tipo di dati. Inter-occlusioni, diverso colore della pelle anche tra utenti della stessa etnia e condizioni di illuminazione instabili, infatti, hanno spesso reso questo problema intrattabile. Altri metodi, invece, hanno risolto i problemi precedenti obbligando l'utente a indossare guanti sensorizzati o ad afferrare strumenti progettati per favorire la localizzazione della mano nella scena. La recente introduzione nel mercato consumer di nuovi sensori di profondità a basso costo, come il Kinect di Microsoft, lo XTION di Asus, il Senz3D di Creative, e il Leap motion, ha aperto la strada a metodi di riconoscimento dei gesti innovativi che sfruttano l'informazione sulla geometria della scena. La maggior parte dei metodi condivide una pipeline di riconoscimento comune basata prima sull'identificazione della mano nella scena, poi nell'estrazione di opportuni descrittori dai campioni della mano e infine nell'utilizzo di opportune tecniche di apprendimento automatico per riconoscere il gesto eseguito all'interno di un ``dizionario dei gesti'' predefinito. Questa tesi, basata sul fondamento precedente, propone un nuovo sistema di riconoscimento dei gesti che sfrutti descrittori sia sul colore sia sulla geometria della scena estratti dai dati provenienti da un sensore di profondità a basso costo. La tesi comincia con l'introduzione del problema del riconoscimento automatico dei gesti, mostrando una panoramica sugli algoritmi allo stato dell'arte e sulla filiera di riconoscimento adottata. Poi, la tesi descrive brevemente i sensori di profondità a basso costo principali e i sistemi usati in letteratura per l'acquisizione di informazioni sul colore e sulla profondità per scopi di riconoscimento dei gesti, evidenziando le loro potenzialità e i loro limiti. In seguito la tesi analizza con maggiore dettaglio i metodi impiegati rispettivamente per la localizzazione della mano nella scena ripresa e la sua segmentazione nelle parti rilevanti. L'algoritmo prima sfrutta l'informazione sul colore della pelle e alcune considerazioni sulla geometria della mano per rimuovere i campioni riferiti allo sfondo, poi localizza accuratamente le regioni del palmo e delle dita e rimuove la regione del braccio. Per la localizzazione del palmo, il metodo fitta il più grande cerchio inscrivibile nella regione del palmo o un'ellisse. Un insieme di feature robuste sul colore e sulla geometria che possono essere estratte dalle regioni del palmo e delle dita, segmentate in precedenza, è poi descritto con accuratezza. Le feature sulla geometria descrivono proprietà del bordo della mano come le sue variazioni di curvatura, le distanze nello spazio 3D o nel piano immagine dei suoi punti dal centro della mano o dal palmo, o estraggono informazioni rilevanti sulla morfologia del palmo e dagli spazi vuoti nel suo guscio convesso. Le feature sul colore sfruttano, invece, gli algoritmi histogram of oriented gradients (HOG), local phase quantization (LPQ) e local ternary patterns (LTP) per ottenere altre informazioni rilevanti sulla tessitura della mano o sulla mappa di profondità trattata come un'immagine in scala di grigi. Feature aggiuntive estratte dai dati provenienti dal Leap Motion completano la caratterizzazione dei gesti per un riconoscimento più affidabile. Inoltre, la tesi descrive anche un nuovo approccio che sfrutta unitamente i dati sulla geometria provenienti dal Leap Motion e quelli sulla profondità provenienti da un sensore di profondità per l'estrazione degli stessi descrittori della profondità con un impegno computazionale inferiore. Questo lavoro in seguito affronta il delicato problema della costruzione di un modello di riconoscimento dei gesti robusto dalle feature descritte in precedenza, usando Support Vector Machines, Random Forests o più potenti insiemi di classificatori. Sono anche considerate tecniche di selezione delle feature per rilevare il minor sotto insieme di feature che permetta l'allenamento di un modello di classificazione senza una significativa perdita di accuratezza. Il metodo di riconoscimento dei gesti proposto, testato su sotto insiemi di segni dell'alfabeto American Sign Language e validato su dati reali, ha riportato accuratezze molto elevate. I risultati hanno anche mostrato che le accuratezze maggiori sono ottenibili con la combinazione di opportuni insiemi di feature complementari e usando insiemi di classificatori. Inoltre, è opportuno notare che l'algoritmo di riconoscimento non è legato a uno specifico sensore o tecnologia adottata per l'acquisizione di dati di profondità. Infine, l'algoritmo di riconoscimento dei gesti può essere eseguito in tempo reale anche in assenza di una completa ottimizzazione, e può essere esteso facilmente in un prossimo futuro con nuovi descrittori e con il supporto per i gesti dinamici.
Mille, Julien. "Modèle déformables pour la segmentation et le suivi en imagerie 2D et 3D". Tours, 2007. http://www.theses.fr/2007TOUR4051.
Pełny tekst źródłaDeformabe models such as active contours are general and powerful tools for image segmentation, enabling to add constraints and prior knowledge about the objects to be segmented. Deformable models are geometrical structures deformed by an evolution method in order to fit the object boundaries. Segmentation is expressed as an optimization problem, which purpose is to determine the curbe of the surface minimizing an objective function (an energy), made up of internal terms related to to model's geometrical smoothness and external terms attaching the model to the image data. In this thesis, we develop an active contour model for 2D segmentation and an active surface model for 3D segmentation, both being based on a unified framework. We also extend the surface model to 3D+T segmentation and tracking. We propose several improvements on the greedy algorithm, a numerical method minimizing the objective function. We also develop an original region-based external term, referring it to as narroy band region energy. It combines local and global features about structures of interest and offers advantages relative to the computational cost and consistency with respect to data
Scholtes, Benjamin. "Développement d'un modèle level set performant pour la modélisation de la recristallisation en 3D". Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM083/document.
Pełny tekst źródłaMechanical and functional properties of metallic materials are strongly related to their microstructures, which are themselves inherited from thermal and mechanical processing. Being able to accurately predict and simulate the microstructure and its heterogeneities after complex forming paths recently became crucial for the metallurgy industry. This is also a real challenge from a numerical point of view which highlights the importance of digital materials in new modeling techniques. In this work, we focus on a recent front-capturing full field model based on the level set (LS) method within a finite element (FE) framework to model recrystallization mechanisms.The strengths of this approach comparatively to the state of the art have motivated the development of a software package called DIGIMU® by the company TRANSVALOR with the support of major industrial companies. However, the main drawback of this approach, common with other front-capturing full field approaches working on unstructured FE meshes, is its important computational cost, especially in 3D.Main purpose of this work was finally to drastically improve the numerical cost of the considered LS-FE formulation in context of unstructured FE meshes. New generic numerical developments have been proposed to improve the global efficiency of the model. The existing 2D LS formulation, already used to model grain growth, static recrystallization and the Smith-Zener pinning effect, has been extended and improved in order to model these mechanisms in 3D for large-scale polycrystals with reasonable computational costs
Desvaux, de Marigny Marie Gaëlle. "Le volume immobilier". Thesis, La Réunion, 2020. http://www.theses.fr/2020LARE0039.
Pełny tekst źródłaIs the space above and below our Land Property saleable? The "Volume immobilier", also called "Volume" or "Air Rights", is an invention of notarial practice. De facto, it is known as the division of space above and below Land’s surface in Real Estate/Property Law [using a 3D Cadastral System]. It was first used by developers to construct complex buildings called "Ensembles immobiliers complexes" in cities and towns. This technique has two advantages. Primo, it allows developers to circumvent the rigidity of Condominium Law, and secundo it allows them to bypass the inalienability of Public Land [Public Domain]. A convincing example of "Air Rights" is the "Quartier de La Défense" in Paris. This technique has recently met with growing success in France Metropolitan and France Overseas. In Reunion Island, it is especially used in photovoltaic projects. This striking success contrasts, however, with the paucity of legal research on the subject. Despite significant difficulties [theoretical and practical], no in-depth research has yet been conducted on the "Volume" itself. Is it a good? Can it be appropriated or sold, regardless of the Land's surface and without any buildings? Can it be sold, rented or given as collateral? So many questions, and more, to study to give this Real Estate Technique the legal security it deserves
Vallières, André. "Dynamique tricomplexe et solides de Platon". Thèse, 2021. http://depot-e.uqtr.ca/id/eprint/9539/1/eprint9539.pdf.
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