Dissertations / Theses on the topic 'Courbes de Hilbert 3D'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 42 dissertations / theses for your research on the topic 'Courbes de Hilbert 3D.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Ramella, Luciana. "Sur le schéma de Hilbert des courbes rationnelles de P3." Nice, 1988. http://www.theses.fr/1988NICE4221.
Full textNguyen, Giap. "Courbes remplissant l'espace et leur application en traitement d'images." Thesis, La Rochelle, 2013. http://www.theses.fr/2013LAROS423/document.
Full textThe space-filling curves are known for the ability to order the multidimensional points on a line while preserving the locality, i.e. the close points are closely ordered on the line. The locality preserving is wished in many applications. Hilbert curve is the best locality preserving space-filling curve. This curve is originally proposed in 2D, i.e. it is only applied to points in a 2D space. For application in the multidimensional case, we propose in this thesis a generalization of Hilbert curve. Generalized curve is based on the essential property of Hilbert curve that creates its level of locality preserving: the adjacency. Thus, it avoids the dependence on the pattern RBG, which is the only pattern of the curve extended by previous researches. The result is a family of curves preserving well the locality. The optimization of the locality preserving is also addressed to find out the best locality preserving curve. For this purpose, we propose a measure of the locality preserving. Based on the parameters, this measure can adapt to different application situations such as the change of metric or locality size. The curve construction is an important part of the thesis. It is the basis of the index calculation used in application. For a rapid index calculation, the self-similar Hilbert curves is used. They are Hilbert curves satisfying the self-similar conditions specified in chapitre 4. The generalized curve is finally applied in image search. It is the question of the content-based image search (CBIR) where each image is characterized by a multidimensionalvector. Images are ordered by the curve of a line, and the search is simplified to the search on an ordered list. By giving an input image, similar images are those corresponding to neighbors of the index of the input. The locality preserving ensures that these indexes correspond to similar images
Le, Tat Thai Thanh Huong. "Courbes gauches avec la bonne postulation." Nice, 2000. http://www.theses.fr/2000NICE5461.
Full textVassallo, Valerio. "Justification de la méthode fonctionnelle pour les courbes gauches." Nice, 1987. http://www.theses.fr/1987NICE4108.
Full textLarri, Gérard. "La classe rationnelle des schémas de Hilbert des courbes planes ou gauches." Nice, 1986. http://www.theses.fr/1986NICE4059.
Full textPéteul, Thomas. "Courbes associées aux modules de Koszul." Versailles-St Quentin en Yvelines, 2000. http://www.theses.fr/2000VERSA009.
Full textNdiaye, Samba. "Utilisation des courbes de Peano-Hilbert pour la gestion des objets dans les bases de données spatiales." Paris 9, 1993. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1993PA090031.
Full textWalkowiak, Yann. "Effectivité dans le théorème d'irréductibilité de Hilbert." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2004. http://tel.archives-ouvertes.fr/tel-00008392.
Full textRamela, Luciana. "Sur le schéma de Hilbert des courbes rationnelles de l'espace projectif de dimension trois." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37617870n.
Full textHeu, Viktoria. "Déformations isomonodromiques des connexions de rang 2 sur les courbes." Phd thesis, Université Rennes 1, 2008. http://tel.archives-ouvertes.fr/tel-00358039.
Full textEn déformant la courbe, la position des pôles et la connexion, nous construisons la déformation isomonodromique universelle d'un tel fibré à connexion. Notre construction spécifique au cas du rang 2 et sans trace est plus élémentaire que la construction en rang quelconque due à B. Malgrange et I. Krichever au sens où elle ne nécessite pas d'analyse de Stokes des singularités irrégulières. De plus, elle englobe le cas des singularités résonantes de manière naturelle.
Nous montrons que le fibré vectoriel sous-jacent à la déformation isomonodromique universelle est génériquement 'maximalement' stable, pourvu que le fibré à connexion initial soit irréductible. À cette fin, nous démontrons une version analytique du résultat de semicontinuité de M. Maruyama, puis nous nous ramenons à un problème de transversalité de feuilletages. À l'aide d'exemples explicites, nous montrons que la condition d'irréductibilité est nécessaire et que l'ensemble analytique des paramètres non génériques au sens ci-dessus peut être non algébrique.
Brugallé, Erwan. "Courbes algébriques réelles et courbes pseudoholomorphes réelles dans les surfaces réglées." Phd thesis, Université Rennes 1, 2004. http://tel.archives-ouvertes.fr/tel-00008652.
Full textAzziz, Saï̈d. "Exemples de composantes irréductibles non réduites du schéma de Hilbert des courbes lisses connexes dans P3." Toulouse 3, 1996. http://www.theses.fr/1996TOU30092.
Full textRoussel, David. "Reconstruction de courbes et de surfaces 3d en stereo-acquisition." Paris 11, 1999. http://www.theses.fr/1999PA112043.
Full textMahé, Valéry. "Calculs dans les jacobiennes de courbes algébriques : applications en géométrie algébrique réelle." Phd thesis, Université Rennes 1, 2006. http://tel.archives-ouvertes.fr/tel-00124040.
Full textComme expliqué par Huisman et Mahé, un polynôme donné P en deux variables à coefficients réels, totalement positif, unitaire, sans facteur carré et de degré multiple de 4 en l'une des variables est une somme de trois carrés de fractions rationnelles si et seulement si la jacobienne d'une certaine courbe hyperelliptique (associée à P) possède un point ”antineutre”.
Grâce à ce critère, et en suivant une méthode de Cassels, Ellison et Pfister, nous résolvons notre problème : à l'aide d'une 2-descente, nous montrons que la jacobienne associée à un certain polynôme positif est de rang de Mordell-Weil nul, puis nous vérifions que cette jacobienne n'a aucun point de torsion antineutre.
Ouled, Azaiez Najib. "Formes quasi-modulaires sur des groupes modulairesco-compacts et restrictions des formes modulaires de Hilbert aux courbes modulaires." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00011122.
Full textformes quasi-modulaires $\widetilde{M}_*(\Gamma)$ gradué par
le poids, sur n'importe quel groupe discret et co-compact
$\Gamma \subset \rm{PSL}(2, \mathbb{R})$ : cet anneau s'avère
être toujours infiniment engendré. On calcule le nombre
de nouveaux générateurs en chaque poids. Le nombre en
question est fixe et est égal à $\dim_{\mathbb{C}} I
/ (I \cap \widetilde{I}^2)$ où $I$ et $\widetilde{I}$
désignent respectivement l'idéal des formes modulaires
sur $\Gamma$ (respectivement l'idéal des formes quasi-modulaires
sur $\Gamma$) en poids positifs. On construit des
anneaux $\widetilde{R}$ finiment engendrés en poids positif
et contenant les anneaux de formes quasi-modulaires sur
des groupes modulaires co-compacts. On étudie aussi
des restrictions des formes modulaires de Hilbert aux
courbes modulaires : on montre que l'espace engendré par
une suite de restrictions des formes modulaires de Hilbert
sur une courbe modulaire
est un sous-espace fermé par crochets de Rankin-Cohen de
l'espace des formes modulaires sur la courbe.
\vskip 2cm
Ouled, Azaiez Najib. "Formes quasi-modulaires sur des groupes modulaires co-compacts et restrictions des formes modulaires de Hilbert aux courbes modulaires." Paris 6, 2005. https://tel.archives-ouvertes.fr/tel-00011122.
Full textAit, Amrane Samir. "Sur le schéma de Hilbert des courbes gauches de degré d et genre g = (d-3)(d-4)/2." Paris 11, 1998. http://www.theses.fr/1998PA112375.
Full textVidaux, Xavier. "Equivalence élémentaire de corps elliptiquesDixième problème de Hilbert pour les fonctions méromorphes p-adiques globales." Angers, 2001. http://www.theses.fr/2001ANGE0025.
Full textMokhtari, Marielle. "Segmentation multi-échelles et approximation de courbes planes, application à la localisation de structures 3D génériques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/NQ57968.pdf.
Full textVieira-Teste, Sylvie. "Représentation de structures géologiques à l'aide de modèles déformables sous contraintes géométriques." Pau, 1997. http://www.theses.fr/1997PAUU3014.
Full textSaini, Laura. "Nouveaux outils pour l'animation et le design : système d'animation de caméra pour la stop motion, fondée sur une interface haptique et design de courbes par des courbes algébriques-trigonométriques à hodographe pythagorien." Phd thesis, Université de Valenciennes et du Hainaut-Cambresis, 2013. http://tel.archives-ouvertes.fr/tel-00835671.
Full textJaramillo, Puentes Andrés. "Rigid isotopy classification of real quintic rational plane curves." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066116/document.
Full textIn order to study the rigid isotopy classes of nodal rational curves of degree $5$ in $\RPP$, we associate to every real rational quintic curve with a marked real nodal point a trigonal curve in the Hirzebruch surface $\Sigma_3$ and the corresponding nodal real dessin on~$\CP/(z\mapsto\bar{z})$. The dessins are real versions, proposed by S. Orevkov~\cite{Orevkov}, of Grothendieck's {\it dessins d'enfants}. The {\it dessins} are graphs embedded in a topological surface and endowed with a certain additional structure. We study the combinatorial properties and decompositions of dessins corresponding to real nodal trigonal curves~$C\subset \Sigma$ in real ruled surfaces~$\Sigma$. Uninodal dessins in any surface with non-empty boundary and nodal dessins in the disk can be decomposed in blocks corresponding to cubic dessins in the disk~$\mathbf{D}^2$, which produces a classification of these dessins. The classification of dessins under consideration leads to a rigid isotopy classification of real rational quintics in~$\RPP$
Drbal, Miroslav. "Indexování objektů v 3D prostoru." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2010. http://www.nusl.cz/ntk/nusl-237135.
Full textDerouet-Jourdan, Alexandre. "Inversion statique de fibres : de la géométrie de courbes 3D à l'équilibre d'une assemblée de tiges mécaniques en contact frottant." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENM043/document.
Full textFibrous structures, which consist of an assembly of flexible slender objects, are ubiquitous in our environment, notably in biological systems such as plants or hair. Over the past few years, various techniques have been developed for digitalizing fibers, either through manual synthesis or with the help of automatic capture. Concurrently, advanced physics based models for the dynamics of entangled fibers have been introduced in order to animate these complex objects automatically. The goal of this thesis is to bridge the gap between those two areas: on the one hand, the geometric representation of fibers; on the other hand, their dynamic simulation. More precisely, given an input fiber geometry assumed to represent a mechanical system in stable equilibrium under external forces (gravity, contact forces), we are interested in the mapping of such a geometry onto the static configuration of a physics-based model for a fiber assembly. Our goal thus amounts to computing the parameters of the fibers that ensure the equilibrium of the given geometry. We propose to solve this inverse problem by modeling a fiber assembly physically as a discrete collection of super-helices subject to frictional contact. We propose two main contributions. The first one deals with the problem of converting the digitalized geometry of fibers, represented as a space curve, into the geometry of the super-helix model, namely a $G^1$ piecewise helical curve. For this purpose we introduce the 3d floating tangents algorithm, which relies upon the co-helicity condition recently stated by Ghosh. More precisely, our method consists in interpolating N+1 tangents distributed on the initial curve by N helices, while minimizing points displacement. Furthermore we complete the partial proof of Ghosh for the co-helicity condition to prove the validity of our algorithm in the general case. The efficiency and accuracy of our method are then demonstrated on various data sets, ranging from synthetic data created by an artist to real data captures such as hair, muscle fibers or lines of the magnetic field of a star. Our second contribution is the computation of the geometry at rest of a super-helix assembly, so that the equilibrium configuration of this system under external forces matches the input geometry. First, we consider a single fiber subject to forces deriving from a potential, and show that the computation is trivial in this case. We propose a simple criterion for stating whether the equilibrium is stable, and if not, we show how to stabilize it. Next, we consider a fiber assembly subject to dry frictional contact (Signorini-Coulomb law). Considering the material as homogeneous, with known mass and stiffness, and relying on an estimate of the geometry at rest, we build a well-posed convex quadratic optimization problem with second order cone constraints. For an input geometry consisting of a few thousands of fibers subject to tens of thousands frictional contacts, we compute within a few seconds a plausible approximation of both the geometry of the fibers at rest and the contact forces at play. We finally apply the combination of our two contributions to the automatic synthesis of natural hairstyles. Our method is used to initialize a physics hair engine with the hair geometry taken from the latest captures of real hairstyles, which can be subsequently animated physically
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.
Full textDeschamps, 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.
Full textIn 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
Boyer, Edmond. "Reconstruction de surfaces d'objets courbes en vision par ordinateur." Phd thesis, Institut National Polytechnique de Lorraine - INPL, 1996. http://tel.archives-ouvertes.fr/tel-00584012.
Full textBoyer, Edmond. "Reconstruction de surfaces d'objets courbes en vision par ordinateur." Phd thesis, Vandoeuvre-les-Nancy, INPL, 1996. https://theses.hal.science/tel-00584012.
Full textTomasini, Arnaud. "Intersections maximales de quadriques réelles." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAD035/document.
Full textReal algebraic geometry is in its simplest definition, the study of sets of solutions of a system of polynomial equations with real coefficients. In this theme, we focus on the intersections of quadrics where already the case of three quadrics remains wide open. Our subject can be summarized as the topological study of real algebraic varieties and interaction between their topology on the one hand and their deformations and degenerations on the other hand, a problem coming from the 16th Hilbert problem and enriched by recent developments. In this thesis, we will focus on maximum intersections of real quadrics and particularly prove the existence of such intersections using research developments made since the late 80. In the case of intersections of three quadrics, we will point the very close link between the intersections on the one hand and on the other plane curves, and show that the study of M-curves (one of the problems of the 16th Hilbert problem) may be done through the study of maximum intersections. Next, we will use the study on nodal plane curves to determine in some cases deformation classes of intersections of three real quadrics
Betina, Adel. "Structure locale des variétés p-adiques de Hecke-Hilbert aux points classiques de poids 1." Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10036/document.
Full textWe show that the Eigenvariety attached to Hilbert modular forms over a totally real field F is smooth at the points corresponding to certain classical weight one theta series and we give a precise criterion for etaleness over the weight space at those points. In the case where the theta series has real multiplication, we construct a non-classical overconvergent generalised eigenform and compute its Fourier coefficient in terms of p-adic logarithms of algebraic numbers. When F = Q, we complete the work of Bellaïche-Dimitrov at the points where the Eigencurve is smooth but not etale over the weight space by giving a precise criterion for the ramication index to be 2. Our approach uses deformations and pseudo-deformations of Galois representations
Chausse, Frédéric. "Reconstruction 3d de courbes parametriques polynomiales par filtrage temporel. Approche par cooperation vision par ordinateur/infographie. Application aux scenes routieres." Clermont-Ferrand 2, 1994. http://www.theses.fr/1994CLF21678.
Full textBallihi, Lahoucine. "Biométrie faciale 3D par apprentissage des caractéristiques géométriques : Application à la reconnaissance des visages et à la classification du genre." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2012. http://tel.archives-ouvertes.fr/tel-00726299.
Full textEtienne, Jimmy. "Tranchage courbe pour la fabrication additive." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0284.
Full textMost additive manufacturing processes fabricate objects by stacking planar layers of solidified material. As a result, produced parts exhibit a so-called staircase effect,which results from sampling slanted surfaces with horizontal planes. This negatively impacts the surface finish and accuracy of a part. While thinner slices reduce this effect, it remains visible in areas where the input shape surfaces almost align with the layers. This horizontal slicing scheme also impacts the resilience of the printed part as layers cannot be aligned to obtain the maximum strength. As with layers, the orientation of trajectories within a slice is often constrained and cannot be freely controlled. In this thesis, we exploit the ability of some additive manufacturing processes to deposit material slightly out of the plane to overcome these limitations. We mainly focus on extrusion-based technologies, particularly Fused Filament Fabrication technology, since most printers in this category can deposit along slightly curved paths underdeposition slope and thickness constraints. Our algorithms are split into two categories,the ones that produce freely oriented trajectories inside a layer and the ones that curve the layers themselves. My first contribution focuses on deposition trajectories inside a layer, allowing the users to control their orientation. This led to two novel infill patterns aiming at two different objectives. The first is a sparse infill that follows a direction field and density field, while the second is a dense, oriented staggered infill pattern with minimal porosity. My second contribution focuses on printing with curved layers, exploring two different approaches. The first one operates directly on the layers, making them either followthe natural slope of the input surface or, on the contrary, intersect the surfaces at a steeper angle, thereby improving the sampling quality. We demonstrate that this approach enforces all fabrication constraints, including the guarantee of generating collision-free toolpaths. The second method builds atop the staggered infill introduced before, generating trajectories with free orientation throughout the part's volume
Motte, François. "De la géométrie à l’arithmétique en théorie inverse de Galois." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I049/document.
Full textWe contribute to the Malle conjecture on the number of finite Galois extensions E of some number field K of Galois group G and of discriminant of norm bounded by y. We establish a lower bound for every group G and every number field K containing a certain number field K'. To achieve this goal, we start from a regular Galois extension F/K(T) that we specialize. We prove a strong version of the Hilbert Irreducibility Theorem which counts the number of specialized extensions and not only the specialization points. We can also prescribe the local behaviour of the specialized extensions at some primes. Consequently, we deduce new results on the local-global Grunwald problem, in particular for some non-solvable groups. To reach our goals, we prove some results in diophantine geometry about the number of integral points on an algebraic curve
Inglebert, Claude. "Suivi et reconstruction de courbes a partir d'une séquence d'images : application au suivi de la signalisation routière." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL016N.
Full textGonzález, Cindy. "Les courbes algébriques trigonométriques à hodographe pythagorien pour résoudre des problèmes d'interpolation deux et trois-dimensionnels et leur utilisation pour visualiser les informations dentaires dans des volumes tomographiques 3D." Thesis, Valenciennes, 2018. http://www.theses.fr/2018VALE0001/document.
Full textInterpolation problems have been widely studied in Computer Aided Geometric Design (CAGD). They consist in the construction of curves and surfaces that pass exactly through a given data set, such as point clouds, tangents, curvatures, lines/planes, etc. In general, these curves and surfaces are represented in a parametrized form. This representation is independent of the coordinate system, it adapts itself well to geometric transformations and the differential geometric properties of curves and surfaces are invariant under reparametrization. In this context, the main goal of this thesis is to present 2D and 3D data interpolation schemes by means of Algebraic-Trigonometric Pythagorean-Hodograph (ATPH) curves. The latter are parametric curves defined in a mixed algebraic-trigonometric space, whose hodograph satisfies a Pythagorean condition. This representation allows to analytically calculate the curve's arc-length as well as the rational-trigonometric parametrization of the offsets curves. These properties are usable for the design of geometric models in many applications including manufacturing, architectural design, shipbuilding, computer graphics, and many more. In particular, we are interested in the geometric modeling of odontological objects. To this end, we use the spatial ATPH curves for the construction of developable patches within 3D odontological volumes. This may be a useful tool for extracting information of interest along dental structures. We give an overview of how some similar interpolating problems have been addressed by the scientific community. Then in chapter 2, we consider the construction of planar C2 ATPH spline curves that interpolate an ordered sequence of points. This problem has many solutions, its number depends on the number of interpolating points. Therefore, we employ two methods to find them. Firstly, we calculate all solutions by a homotopy method. However, it is empirically observed that only one solution does not have any self-intersections. Hence, the Newton-Raphson iteration method is used to directly compute this \good" solution. Note that C2 ATPH spline curves depend on several free parameters, which allow to obtain a diversity of interpolants. Thanks to these shape parameters, the ATPH curves prove to be more exible and versatile than their polynomial counterpart, the well known Pythagorean-Hodograph (PH) quintic curves and polynomial curves in general. These parameters are optimally chosen through a minimization process of fairness measures. We design ATPH curves that closely agree with well-known trigonometric curves by adjusting the shape parameters. We extend the planar ATPH curves to the case of spatial ATPH curves in chapter 3. This characterization is given in terms of quaternions, because this allows to properly analyze their properties and simplify the calculations. We employ the spatial ATPH curves to solve the first-order Hermite interpolation problem. The obtained ATPH interpolants depend on three free angular values. As in the planar case, we optimally choose these parameters by the minimization of integral shape measures. This process is also used to calculate the C1 interpolating ATPH curves that closely approximate well-known 3D parametric curves. To illustrate this performance, we present the process for some kind of helices. In chapter 4 we then use these C1 ATPH splines for guiding developable surface patches, which are deployed within odontological computed tomography (CT) volumes, in order to visualize information of interest for the medical professional. Particularly, we construct piecewise conical surfaces along smooth ATPH curves to display information related to the anatomical structure of human jawbones. This information may be useful in clinical assessment, diagnosis and/or treatment plan. Finally, the obtained results are analyzed and conclusions are drawn in chapter 5
Pelcat, Jimmy. "Reconstruction 3D et production de carte dense de disparité en stéréovision non-alignée pour des applications industrielles de localisation 3D et d'analyse de surface." Thesis, Rouen, INSA, 2012. http://www.theses.fr/2012ISAM0025/document.
Full textIn industrial vision, many applications for measuring and quality control are moving to three-dimensional problems. Stereovision systems are technological solutions that attract industry by their mechanical simplicity. Two static cameras placed at strategic locations may be sufficient to address this problem although the industrial constraints imposed to respect a short processing time and precise measurements. The diversity of applications lead us to consider two approaches to resolve the two types of application. The first technique consists in the 3D reconstruction from pairs of image points which correspond in both images. It is intended to address the problem of 3D measurement. The methods of monocular calibration and 3D triangulation are the basis of 3D reconstruction. We study the accuracy and its evolution according to the capture system pose compared to the observed scene. The second technique is to construct disparity maps to address problems of building profile and default analysis. The alignment constraint of cameras needed to accelerate the process of matching involves the use of methods of stereoscopic calibration and image rectification. We study the impact of alignment on the quality of the rectification. The production of dense disparity map is based on the stereo-correlation techniques. We show the limits of the use of a squared correlation kernel and propose an alternative production of two dense disparity maps from two mono-directional kernels, improving the measurement of disparity around edges and occlusions
Fourtinon, Luc. "3D conformal antennas for radar applications." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2017. http://www.theses.fr/2017IMTA0060/document.
Full textEmbedded below the radome of a missile, existing RF-seekers use a mechanical rotating antenna to steer the radiating beam in the direction of a target. Latest research is looking at replacing the mechanical antenna components of the RF-seeker with a novel 3D conformal antenna array that can steer the beam electronically. 3D antennas may offer significant advantages, such as faster beam steering and better coverage but, at the same time, introduce new challenges resulting from a much more complex radiation pattern than that of 2D antennas. Thanks to the mechanical system removal, the new RF-seeker has a wider available space for the design of a new 3D conformal antenna. To take best benefits of this space, different array shapes are studied, hence the impact of the position, orientation and conformation of the elements is assessed on the antenna performance in terms of directivity, ellipticity and polarisation. To facilitate this study of 3D conformal arrays, a Matlab program has been developed to compute the polarisation pattern of a given array in all directions. One of the task of the RF-seeker consists in estimating the position of a given target to correct the missile trajectory accordingly. Thus, the impact of the array shape on the error between the measured direction of arrival of the target echo and its true value is addressed. The Cramer-Rao lower bound is used to evaluate the theoretical minimum error. The model assumes that each element receives independently and allows therefore to analyse the potential of active 3D conformal arrays. Finally, the phase monopulse estimator is studied for 3Dconformal arrays whose quadrants do not have the same characteristics. A new estimator more adapted to non-identical quadrants is also proposed
Gallardo, Mathias. "Contributions to Monocular Deformable 3D Reconstruction : Curvilinear Objects and Multiple Visual Cues." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC021/document.
Full textMonocular deformable 3D reconstruction is the general problem of recovering the 3D shape of a deformable object from monocular 2D images. Several scenarios have emerged: the Shape-from-Template (SfT) and the Non-Rigid Structure-from-Motion (NRSfM) are two approaches intensively studied for their practicability. The former uses a single image depicting the deforming object and a template (a textured 3D shape of this object in a reference pose). The latter does not use a template, but uses several images and recovers the 3D shape in each image. Both approaches rely on the motion of correspondences between the images and deformation priors, which restrict their use to well-textured surfaces which deform smoothly. This thesis advances the state-of-the-art in SfT and NRSfM in two main directions. The first direction is to study SfT for the case of 1D templates (i.e. curved, thin structures such as ropes and cables). The second direction is to develop algorithms in SfT and NRSfM that exploit multiple visual cues and can solve complex, real-world cases which were previously unsolved. We focus on isometric deformations and reconstruct the outer part of the object. The technical and scientific contributions of this thesis are divided into four parts. The first part of this thesis studies the case of a curvilinear template embedded in 2D or 3D space, referred to Curve SfT. We propose a thorough theoretical analysis and practical solutions for Curve SfT. Despite its apparent simplicity, Curve SfT appears to be a complex problem: it cannot be solved locally using exact non-holonomic partial differential equation and is only solvable up to a finite number of ambiguous solutions. A major technical contribution is a computational solution based on our theory, which generates all the ambiguous solutions.The second part of this thesis deals with a limitation of SfT methods: reconstructing creases. This is due to the sparsity of the motion constraint and regularization. We propose two contributions which rely on a non-convex energy minimization framework. First, we complement the motion constraint with a robust boundary contour constraint. Second, we implicitly model creases with a dense mesh-based surface representation and an associated robust smoothing constraint, which deactivates curvature smoothing automatically where needed, without knowing a priori the crease location. The third part of this thesis is dedicated to another limitation of SfT: reconstructing poorly-textured surfaces. This is due to correspondences which cannot be obtained so easily on poorly-textured surfaces (either sparse or dense). As shading reveals details on poorly-textured surfaces, we propose to combine shading and SfT. We have two contributions. The first is a cascaded initialization which estimates sequentially the surface's deformation, the scene illumination, the camera response and then the surface albedos from deformed monocular images. The second is to integrate shading to our previous energy minimization framework for simultaneously refining deformation and photometric parameters.The last part of this thesis relaxes the knowledge of the template and addresses two limitations of NRSfM: reconstructing poorly-textured surfaces with creases. Our major contribution is an extension of the second framework to recover jointly the 3D shapes of all input images and the surface albedos without any template
Peter, Christian. "Etude et réalisation d'un appareil d'acquisition automatique de séries de contours tridimensionnels de patients : aide à la radiotherapie et àla chirurgie de reconstruction mammaire en cancerologie." Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPL130N.
Full textMachu, François-Xavier. "Moduli of connections." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10024/document.
Full textThe logarithmic connections studied in Chapter 1 are direct images of regular connections on line bundles over genus-2 double covers of the elliptic curve. We give an explicit parametrization of ail such connections, determine their monodromy, differential Galois group and the underlying rank-2 vector bundle. The latter is described in terms of elementary transforms. The question of its (semi)-stability is addressed. ln Chapter 2, we construct the Kuranishi spaces (or versai deformations) for the four connection classes: the class of meromorphic connections with fixed divisor of poles D and its subclasses of integrable. integrable logarithmic and integrable logarithmic connections with a parabolic structure over D. ln Chapter 3, we use the Kuranishi spaces to describe the local structure of the moduli spaces of connections and their relation to the moduli spaces of underlying vector bundles
Manzaroli, Matilde. "Real algebraic curves in real del Pezzo surfaces." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX017/document.
Full textThe study of the topology of real algebraic varieties dates back to the work of Harnack, Klein and Hilbert in the 19th century; in particular, the isotopy type classification of real algebraic curves with a fixed degree in RP2 is a classical subject that has undergone considerable evolution. On the other hand, apart from studies concerning Hirzebruch surfaces and at most degree 3 surfaces in RP3, not much is known for more general ambient surfaces. In particular, this is because varieties constructed using the patchworking method are hypersurfaces of toric varieties. However, there are many other real algebraic surfaces. Among these are the real rational surfaces, and more particularly the $mathbb{R}$-minimal surfaces. In this thesis, we extend the study of the topological types realized by real algebraic curves to the real minimal del Pezzo surfaces of degree 1 and 2. Furthermore, we end the classification of separating and non-separating real algebraic curves of bidegree $(5,5)$ in the quadric ellipsoid