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Merabti, Billal. "Style-driven virtual camera control in 3D environments". Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S129/document.
Pełny tekst źródłaAutomatically computing a cinematographically consistent sequence of shots, over a set of actions occurring in a 3D world, is a complex task which requires not only the computation of appropriate shots (viewpoints) and appropriate transitions between shots (cuts), but the ability to encode and reproduce elements of cinematographic style. The models proposed in the literature, generally rule-based, provide limited functionalities to build sequences of shots. These approaches are not designed in mind to easily learn elements of cinematographic style, nor do they allow to perform significant variations in style over the same sequence of actions. In this thesis, we first propose a data-driven model for automated cinematography (framing and editing) that can compute significant variations in terms of cinematographic style, with the ability to control the duration of shots and the possibility to add specific constraints to the desired sequence. By using a Hidden Markov Model representation of the editing process, we demonstrate the possibility of easily reproducing elements of style extracted from real movies. The proposed model is more elaborate in handling dialogue scenes than existing representations, and proves to be more expressive in its ability to precisely encode elements of cinematographic style. Then, we introduce an extension of this model to account for more complex environments (more than dialogues). To this end, we use a more general statistical model: Dynamic Bayesian Network, which enlarges considerably the possibilities in editing and film analysis. We finally designed a data annotation tool and a format to easily create film annotations that would be used for data-driven cinematography or film analysis
Viguié, Guillaume. "Apport de la programmation graphique pour la reconstruction rapide d'images 3D en tomographie par émission monophotonique". Toulouse 3, 2008. http://thesesups.ups-tlse.fr/410/.
Pełny tekst źródłaSingle Photon Emission Computed Tomography (SPECT) is a non-invasive medical imaging modality which visualizes radioactively labeled molecules administered to a patient. Photons emitted by the radio-isotopes are detected by a rotating camera system equipped by a lead collimator. A mathematical inversion technique is used to reconstruct the unknown 3D distribution of radio-activity in the body from the series of 2D projection images recorded by the system. In this process, image quality may be affected by two major degrading phenomena, collimator blurring, and attenuation of photons via the photoelectric and the Compton effects. The aim of this thesis is to enhance the quality of SPECT reconstructed images by reducing these degrading effects. Several methods have been proposed to correct the effects of collimator blurring. The most efficient is to include a physical model of the collimator response function and to reconstruct images by an iterative method, which includes this model. Here we extend this line by improving convergence. The use of graphic cards can accelerate this process by a factor of 100. We have implemented non-uniform attenuation correction methods which do not need additional transmission measurements, but uses emission data only. Reconstruction of activity based on emission data is a difficult non-linear ill-posed inverse problem. Two approaches have been tested, one based on non-linear optimization techniques, a second based on iterative techniques similar to those currently in use. The iterative technique performed more stably and generally produced better results. In simulated studies we were able to demonstrate an improvement over existing techniques, while this rests to be established in the case of clinical data. .
Guo, Jinjiang. "Contributions to objective and subjective visual quality assessment of 3d models". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI099.
Pełny tekst źródłaIn computer graphics realm, three-dimensional graphical data, generally represented by triangular meshes, have become commonplace, and are deployed in a variety of application processes (e.g., smoothing, compression, remeshing, simplification, rendering, etc.). However, these processes inevitably introduce artifacts, altering the visual quality of the rendered 3D data. Thus, in order to perceptually drive the processing algorithms, there is an increasing need for efficient and effective subjective and objective visual quality assessments to evaluate and predict the visual artifacts. In this thesis, we first present a comprehensive survey on different sources of artifacts in digital graphics, and current objective and subjective visual quality assessments of the artifacts. Then, we introduce a newly designed subjective quality study based on evaluations of the local visibility of geometric artifacts, in which observers were asked to mark areas of 3D meshes that contain noticeable distortions. The collected perceived distortion maps are used to illustrate several perceptual functionalities of the human visual system (HVS), and serve as ground-truth to evaluate the performances of well-known geometric attributes and metrics for predicting the local visibility of distortions. Our second study aims to evaluate the visual quality of texture mapped 3D model subjectively and objectively. To achieve these goals, we introduced 136 processed models with both geometric and texture distortions, conducted a paired-comparison subjective experiment, and invited 101 subjects to evaluate the visual qualities of the models under two rendering protocols. Driven by the collected subjective opinions, we propose two objective visual quality metrics for textured meshes, relying on the optimal combinations of geometry and texture quality measures. These proposed perceptual metrics outperform their counterparts in term of the correlation with the human judgment
Lescoat, Thibault. "Geometric operators for 3D modeling using dictionary-based shape representations". Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT005.
Pełny tekst źródłaIn this thesis, we study high-level 3D shape representations and developed the algorithm primitives necessary to manipulate shapes represented as a composition of several parts. We first review existing representations, starting with the usual low-level ones and then expanding on a high-level family of shape representations, based on dictionaries. Notably, we focus on representing shapes via a discrete composition of atoms from a dictionary of parts.We observe that there was no method to smoothly blend non-overlapping atoms while still looking plausible. Indeed, most methods either required overlapping parts or do not preserve large-scale details. Moreover, very few methods guaranteed the exact preservation of the input, which is very important when dealing with artist-authored meshes to avoid destroying the artist's work. We address this challenge by proposing a composition operator that is guaranteed to exactly keep the input while also propagating large-scale details.To improve the speed of our composition operator and allow interactive edition, we propose to simplify the input parts prior to completing them. This allow us to interactively previsualize the composition of large meshes. For this, we introduce a method to simplify a detailed mesh to a coarse one by preserving the large details. While more constrained than related approaches that do not produce a mesh, our method still yields faithful outputs
Lanterne, Célestin. "Réparation et optimisation de maillages 3D pour l'impression 3D". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0454.
Pełny tekst źródła3D printers use 3D models in the form of meshes to define the geometry and the appearance of objects to be printed. A 3D mesh must have some topological properties so that the geometry it represents could be printable and the geometry itself must respect certain conditions to be printable. These properties and conditions may vary depending on the 3D printing technologies in use.Many 3D meshes used for printing were not initially designed for this purpose application. The main primary use of these meshes is visualization, which does not require the same topological properties and geometric conditions. The subject of this thesis is the repair of these meshes to make them printable.A repair chain including several steps was designed for this purpose. Non-manifold conditions are repaired by extracting related components (surfaces). The boundaries of surfaces are detected and classified according to the best repair to be applied on each. The boundaries of surfaces are repaired according to their classification either by a filling method or by an offset method. The weakness of the geometry is detected and controlled
Angles, Baptiste. "Modélisation géométrique par primitives". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30060.
Pełny tekst źródłaBoth man-made or natural objects contain repeated geometric elements that can be interpreted as primitive shapes. Plants, trees, living organisms or even crystals, showcase primitives that repeat themselves. Primitives are also commonly found in man-made environments because architects tend to reuse the same patterns over a building and typically employ simple shapes, such as rectangular windows and doors. During my PhD I studied geometric primitives from three points of view: their composition, simulation and autonomous discovery. In the first part I present a method to reverse-engineer the function by which some primitives are combined. Our system is based on a composition function template that is represented by a parametric surface. The parametric surface is deformed via a non-rigid alignment of a surface that, once converged, represents the desired operator. This enables the interactive modeling of operators via a simple sketch, solving a major usability gap of composition modeling. In the second part I introduce the use of a novel primitive for real-time physics simulations. This primitive is suitable to efficiently model volume-preserving deformations of rods but also of more complex structures such as muscles. One of the core advantages of our approach is that our primitive can serve as a unified representation to do collision detection, simulation, and surface skinning. In the third part I present an unsupervised deep learning framework to learn and detect primitives. In a signal containing a repetition of elements, the method is able to automatically identify the structure of these elements (i.e. primitives) with minimal supervision. In order to train the network that contains a non-differentiable operation, a novel multi-step training process is presented
Holländer, Matthias. "Synthèse géométrique temps réel". Thesis, Paris, ENST, 2013. http://www.theses.fr/2013ENST0009/document.
Pełny tekst źródłaEal-time geometry synthesis is an emerging topic in computer graphics.Today's interactive 3D applications have to face a variety of challengesto fulfill the consumer's request for more realism and high quality images.Often, visual effects and quality known from offline-rendered feature films or special effects in movie productions are the ultimate goal but hard to achieve in real time.This thesis offers real-time solutions by exploiting the Graphics Processing Unit (GPU)and efficient geometry processing.In particular, a variety of topics related to classical fields in computer graphics such assubdivision surfaces, global illumination and anti-aliasing are discussedand new approaches and techniques are presented
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
Entem, Even. "Interprétation et modélisation 3D automatique à partir de dessins au trait de formes organiques". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAM054/document.
Pełny tekst źródłaDrawing is the most common way to communicate about shapes.Thus, using sketching as a tool in the process of modeling 3D content is an attractive approach.However in the world of machines, drawings are still difficult to interpret as shape depictions.This has been the challenge tackled by many different research works since leveraging the little we know about perception is non trivial.My thesis focuses on pushing the limits of what can be inferred from single drawings of smooth shapes without any help from the user.In a first attempt we chose to select a category of shape namely animals and other creatures for which prior knowledge helps to solve the problem.Then we proposed to generalize parts of the solution to tackle the case of free form organic shapes.This manuscript thus presents the respective solutions we developed. The first one is able to infer plausible 3D models of animals from a single side-view sketch using anatomic principles to both interpret the drawing's elements and infer depth offsets between these elements.The second is an approach to decompose depictions of smooth shapes with non trivial cusp points into a set of structural parts' silhouettes ordered in depth, which can be used for editing and animation purposes.Many related ideas were explored on the way, and the ones presented in this manuscript leaves me confident about the future of this field of research
Fondevilla, Amélie. "Modélisation 3D d'objets cousus à partir d'un unique croquis". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAM070.
Pełny tekst źródłaThe efficient creation of virtual 3D content is a major issue in Computer Graphics industry and research. This thesis addresses the modeling of sewed 3D objects such as clothes, shoes or accessories from 2D sketched inputs. While existing related approaches are either based on multi-view inputs or on character dependent interfaces, we propose in this thesis to start from an annotated single-view input in order to create 3D content satisfying geometric constraints that are specific to fabric, such as developability, or fold appearance and distribution. Our goal is to exploit the expressiveness user-drawn sketches to guide the modeling of plausible objects, using a priori geometric knowledge.We first present a single-view reconstruction approach for symmetric piece-wise developable objects from an annotated photo. Using the assumption of mirror-symmetry along with properties of smooth developable surfaces, we propose a system able to lift in 3 the silhouette, borders and seams drawn on the picture and reconstruct the surface of the object. Our method also provides topology information on the object, allowing the computation of 2D patterns for each piece of developable surface, which is necessary for manufacturing.While most of existing sketch-based modeling methods for garments aim at reconstructing border lines drawn on top of a view of the 3D virtual mannequin to be dressed, our approach uses a single 2D sketch as input. Our method first extracts generic features relative to the style of the sketched garment expressed as garment proportions, tight areas, silhouette shapes and folds. In particular, we propose a dedicated approach to extract robustly folds characteristics, even in the case of garment with deep folds leading to partially occluded garment borders. In a second step, we synthesize on a target virtual character a 3D garment surface exhibiting similar style, while adapting to the target pose and morphology that may be drastically different from the one depicted the sketch
Holländer, Matthias. "Synthèse géométrique temps réel". Electronic Thesis or Diss., Paris, ENST, 2013. http://www.theses.fr/2013ENST0009.
Pełny tekst źródłaEal-time geometry synthesis is an emerging topic in computer graphics.Today's interactive 3D applications have to face a variety of challengesto fulfill the consumer's request for more realism and high quality images.Often, visual effects and quality known from offline-rendered feature films or special effects in movie productions are the ultimate goal but hard to achieve in real time.This thesis offers real-time solutions by exploiting the Graphics Processing Unit (GPU)and efficient geometry processing.In particular, a variety of topics related to classical fields in computer graphics such assubdivision surfaces, global illumination and anti-aliasing are discussedand new approaches and techniques are presented
Zanuttini, Antoine. "Du photoréalisme au rendu expressif en image 3D temps réel dans le jeu vidéo : programmation graphique pour la profondeur de champ, la matière, la réflexion, les fluides et les contours". Paris 8, 2012. http://octaviana.fr/document/171326563#?c=0&m=0&s=0&cv=0.
Pełny tekst źródłaThis study seeks to go beyond the standardized video games aesthetics by adding new depiction techniques for real-time digital imagery. Photorealistic rendering is often limited in control and flexibility for an artist who searches beyond fidelity to real. Achieving credibility and immersion will then often require stylization for the view to be more convincing and aesthetic. Expressive rendering goes further by taking care of the artist's personal vision, while being based on some real life attributes and phenomena, altering them at the same time. We will show that photorealism and expressive rendering join and complete each other under numerous aspects. Three themes related to photorealism will be presented, then some personal original techniques will be introduced. The theme of depth of field will lead us to consider the shape of the virtual camera's lens through the Hexagonal Summed Area Table algorithm. We will then look at material, light and especially ambient and specular reflections and the importance of parallax correction with regards to them. Our third theme will be the rendering of fluid motion and the advection of textures according to the flow for easy and efficient detail addition. These three subjects will then be integrated into expressive rendering and used as expression tools for the artist, through the creation of a dream effect, of screen-space rendered fluids, and of hatched material shading. Finally, we will show our creations specifically dedicated to expressive rendering and stroke stylization
Legrand, Hélène. "Algorithmes parallèles pour le traitement rapide de géométries 3D". Electronic Thesis or Diss., Paris, ENST, 2017. http://www.theses.fr/2017ENST0053.
Pełny tekst źródłaOver the last twenty years, the main signal processing concepts have been adapted for digital geometry, in particular for 3D polygonal meshes. However, the processing time required for large models is significant. This computational load becomes an obstacle in the current context, where the massive amounts of data that are generated every second may need to be processed with several operators. The ability to run geometry processing operators with strong time constraints is a critical challenge in dynamic 3D systems. In this context, we seek to speed up some of the current algorithms by several orders of magnitude, and to reformulate or approximate them in order to reduce their complexity or make them parallel. In this thesis, we are building on a compact and effective object to analyze 3D surfaces at different scales : error quadrics. In particular, we propose new high performance algorithms that maintain error quadrics on the surface to represent the geometry. One of the main challenges lies in the effective generation of the right structures for parallel processing, in order to take advantage of the GPU
Roussellet, Valentin. "Implicit muscle models for interactive character skinning". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30055/document.
Pełny tekst źródłaSurface deformation, or skinning is a crucial step in 3D character animation. Its role is to deform the surface representation of a character to be rendered in the succession of poses specified by an animator. The quality and plausiblity of the displayed results directly depends on the properties of the skinning method. However, speed and simplicity are also important criteria to enable their use in interactive editing sessions. Current skinning methods can be divided in three categories. Geometric methods are fast and simple to use, but their results lack plausibility. Example-based approaches produce realistic results, yet they require a large database of examples while remaining tedious to edit. Finally, physical simulations can model the most complex dynamical phenomena, but at a very high computational cost, making their interactive use impractical. The work presented in this thesis are based on, Implicit Skinning, is a corrective geometric approach using implicit surfaces to solve many issues of standard geometric skinning methods, while remaining fast enough for interactive use. The main contribution of this work is an animation model that adds anatomical plausibility to a character by representing muscle deformations and their interactions with other anatomical features, while benefiting from the advantages of Implicit Skinning. Muscles are represented by an extrusion surface along a central axis. These axes are driven by a simplified physics simulation method, introducing dynamic effects, such as jiggling. The muscle model guarantees volume conservation, a property of real-life muscles. This model adds plausibility and dynamics lacking in state-of-the-art geometric methods at a moderate computational cost, which enables its interactive use. In addition, it offers intuitive shape control to animators, enabling them to match the results with their artistic vision
Vaillant, Rodolphe. "Implicit skinning : character skin deformation guided by 3D scalar fields". Thesis, Toulouse 3, 2015. http://hdl.handle.net/1828/7336.
Pełny tekst źródłaGraduate
Ecormier-Nocca, Pierre. "Authoring consistent, animated ecosystems : Efficient learning from partial data". Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX078.
Pełny tekst źródłaWith recent increases in computing power, virtual worlds are now larger and more complex than ever. As such content becomes widespread in many different media, the expectation of realism has also dramatically increased for the end user.As a result, a large body of work has been accomplished on the modeling and generation of terrains and vegetation, sometimes also considering their interactions. However, animals have received far less attention and are often considered in isolation. Along with a lack of authoring tools, this makes the modeling of ecosystems difficult for artists, who are either limited in their creative freedom or forced to break biological realism.In this thesis, we present new methods suited to the authoring of ecosystems, allowing creative freedom without discarding biological realism. We provide data-centered tools for an efficient authoring, while keeping a low data requirement. By taking advantage of existing biology knowledge, we are able to guarantee both the consistency and quality of the results.We present dedicated methods for precise and intuitive instantiation of static and animated elements. Since static elements, such as vegetation, can exhibit complex interactions, we propose an accurate example-based method to synthesize complex and potentially overlapping arrangements. We apply a similar concept to the authoring of herds of animals, by using photographs or videos as input for example-based synthesis. At a larger scale, we use biological data to formulate a unified pipeline handling the global instantiation and long-term interactions of vegetation and animals. While this model enforces biological consistency, we also provide control by allowing manual editing of the data at any stage of the process.Our methods provide both user control and realism over the entire ecosystem creation pipeline, covering static and dynamic elements, as well as interactions between themselves and their environment. We also cover different scales, from individual placement and movement of elements to management of the entire ecosystem. We validate our results with user studies and comparisons with both real and expert data
Lejemble, Thibault. "Analyse multi-échelle de nuage de points". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30184.
Pełny tekst źródła3D acquisition techniques like photogrammetry and laser scanning are commonly used in numerous fields such as reverse engineering, archeology, robotics and urban planning. The main objective is to get virtual versions of real objects in order to visualize, analyze and process them easily. Acquisition techniques become more and more powerful and affordable which creates important needs to process efficiently the resulting various and massive 3D data. Data are usually obtained in the form of unstructured 3D point cloud sampling the scanned surface. Traditional signal processing methods cannot be directly applied due to the lack of spatial parametrization. Points are only represented by their 3D coordinates without any particular order. This thesis focuses on the notion of scale of analysis defined by the size of the neighborhood used to locally characterize the point-sampled surface. The analysis at different scales enables to consider various shapes which increases the analysis pertinence and the robustness to acquired data imperfections. We first present some theoretical and practical results on curvature estimation adapted to a multi-scale and multi-resolution representation of point clouds. They are used to develop multi-scale algorithms for the recognition of planar and anisotropic shapes such as cylinders and feature curves. Finally, we propose to compute a global 2D parametrization of the underlying surface directly from the 3D unstructured point cloud
Lacoste, Julien. "Préservation de détails par placage d'octree-textures". Phd thesis, Université de Pau et des Pays de l'Adour, 2008. http://tel.archives-ouvertes.fr/tel-00461725.
Pełny tekst źródłaEsnault, Noémie. "Production automatique d'interfaces graphiques 3D pour le Web". Phd thesis, Université Rennes 1, 2011. http://tel.archives-ouvertes.fr/tel-00574772.
Pełny tekst źródłaBeguet, Florian. "Modélisation et description par graphes pour des formes géométriques complexes : application aux structures de l'oreille". Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0563.
Pełny tekst źródłaThis thesis work is divided into two parts and deals with the reconstruction and description of complex geometric shapes. The first part presents the development of a multi-structure reconstruction approach of volumetric data from deformable models. This approach is applied on volumes obtained by cone beam tomography for the reconstruction of structures of the inner ear and the ossicular chain. The user first positions a set of control points in the volume for each structure of the ear. The meshes are then iteratively reshaped in two steps: a segmentation step, which allows to find the limits of the structure in the volume; and a regularization step, which allows to maintain the general shape of the structure. Finally, the quality of the reconstructions, the reproducibility and the influence of the parameters are estimated and compared to the literature. The second part presents the development of a 3D shape analysis and comparison approach. It is based on the construction of a Reeb shape index graph that allows to characterize in a compact way both the geometry and the topology of the object. This graph is partitioned into several subgraphs to obtain a local description of the surface regions. The subgraphs of two similar surfaces are matched according to their similarity to perform the comparison. This approach is applied to the detection of malformation on the semicircular canals between a group of asymptomatic patients and a group of patients with scoliosis
Le, Naour Thibaut. "Utilisation des relations spatiales pour l'analyse et l'édition de mouvement". Phd thesis, Université de Bretagne Sud, 2013. http://tel.archives-ouvertes.fr/tel-00916514.
Pełny tekst źródłaRossi, Romain. "Reconstruction 3D volumétrique par vision omnidirectionnelle sur architecture massivement parallèle". Rouen, 2011. http://www.theses.fr/2011ROUES025.
Pełny tekst źródła3D reconstruction of an unknown scene is a classical computer vision problem. Usual solutions, which use a pair of cameras in stereoscopic configuration and an algorithm relying on image disparities, don't allow to create a densely sampled 3D model. Moreover, processing this model in real-time is a complex task which often needs an implementation on dedicated hardware (FPGA or DSP), very powerful but hard to use. In this thesis, we propose a volumetric reconstruction method aiming to produce a high-resolution 3D model of the scene surrounding a mobile robot. A pair of catadioptric cameras allows panoramic acquisition of the whole scene. The reconstruction algorithm, adapted for the massively-parallel architecture of a very powerful and inexpensive Graphical Processing Unit (GPU) tries to limit data-dependencies to improve performances. This reconstruction method also benefit from additional pictures, taken as the robot moves in the scene, to incrementally improve the 3D model. The final results are qualitatively equivalent to the ones obtained with classical methods, but our approach allows a 3D resolution far better (500x500x200 voxels) with a very short running time (about 5 seconds for each reconstruction). The real-time objective (2 reconstructions per second) can even be reached for a lower-resolution (150x150x150 voxels). Experimental results on a real image validate the proposed approach
Knödel, Sebastian. "Beyond desktop : designing novel user interfaces to enhance 3D exploration". Thesis, Bordeaux 1, 2009. http://www.theses.fr/2010BOR13912/document.
Pełny tekst źródłaOur research concerns the investigation of new approaches that enhance 3D exploration in virtual environments for users. Thereby, we concentrate on design of novel transversal 3D interaction techniques that are simple, efficient and benefit from new input technology, like tactile interfaces. Our approach allows users to perform complex 3D interaction using single and multiple 2D touch input. Users carry out simple touch, stroke or sketch-based gestures to interact with content. To draw conclusions about the usability of our interfaces we evaluate the interaction techniques by conducting users studies. In addition, we adopt different traditional and illustrative visualization techniques to highlight object characteristics in focus while preserving context information. Furthermore, we propose new methods for collaboration between users, who interact together with 3D data using varying technology, from small mobile devices to immersive virtual environments
Barré, Sébastien. "Modélisation, fusion et reconstruction 3D pour l'aide à la chirurgie maxillo-faciale". Poitiers, 2001. http://www.theses.fr/2001POIT2264.
Pełny tekst źródłaAjaj, Rami. "TEAMViz : systèmes multi-dispositifs, multi-vues et multi-surfaces pour la visualisation interactive de scène 3D". Paris 11, 2009. http://www.theses.fr/2009PA112234.
Pełny tekst źródłaVirtual environments are immersive and intuitive spaces but the design of edition and navigation interfaces is complex because of the diversity of interaction devices and tasks to realize. Direct-touch tabletop devices offer intuitive interactions but limited number of degrees of freedom. In order to cover the interaction need in 3D environments, we have designed TEAMViz (Tabletop Environment Augmented with Mural Visualisation). TEAMViz combine interactions performed through a 3D perspective view of the same scene dispayed on a wall screen. The main contribution of our research is the conception of a design space dedicated to the combination of interactions that use multiple input devices and multiple views displayed on distinct display surfaces for edition and navigation tasks in virtual environments. This design space considers the relation between input degrees of freedom in the real-world and the tasks to achieve as well as the relations between views. It allows to combine interactions realized using devices for which an important input/output coupling is required as for tactile surfaces
Lavarec, Erwann. "Estimation de mouvements 3D à l'aide d'une caméra et de capteurs proprioceptifs". Montpellier 2, 2001. http://www.theses.fr/2001MON20201.
Pełny tekst źródłaHillaire, Sébastien. "Contribution à l'étude des modèles d'attention visuelle et du suivi de regard pour améliorer le retour visuel dans les applications 3D interactives". Rennes, INSA, 2011. http://www.theses.fr/2011ISAR0002.
Pełny tekst źródłaIn virtual reality, the interaction between a human and a computer can be achieved through multiple sensory channels. The visual channel is generally used in order to provide a visual feedback to the user interacting with a virtual environment. The goal of this thesis is to improve this visual feedback by taking into account user’s visual attention in an interactive manner. The first part of this thesis is dedicated to human attention. We wanted to evaluate in real-time the gaze point of a user navigating in a 3D virtual environment using a first-person view. We have first studied human visual attention when walking in a virtual environment and have shown that there are several common behaviors when compared to a real pedestrian walk. We have then proposed a model in order to simulate this behavior. We have included this component in a novel visual attention model able to predict, in real-time, the attention of a user navigating in a virtual environment. Our evaluation has shown that our model was able to predict the users' visual attention more efficiently than existing models. Finally, we have proposed a novel use of visual attention models in order to improve the accuracy of any gaze tracking systems. Our study has shown that our approach could improve the global accuracy of these systems. In the second part of this thesis, we have researched a novel way to improve the visual feedback to the users in order to improve their immersion feelings and perception of a virtual environment. We have proposed a novel use of the gaze point in order to simulate natural visual effects present in human vision: a depth-of-field blur effect and a compensated camera motion. Our study has shown that these effects were strongly preferred by participants when they were computed based on their gaze point, in a more interactive manner
Auclair, Adrien. "Méthodes rapides pour la recherche des plus proches voisins SIFT : application à la recherche d'images et contributions à la reconstruction 3D multi-vues". Paris 5, 2009. http://www.theses.fr/2009PA05S012.
Pełny tekst źródłaIn the first part of this thesis, we are concerned by the nearest neighbour problem, applied on local image descriptors. We restricted ourselves to the SIFT descriptors because of its efficiency. The application of this work is the retrieval of similar images in large databases. First, we compare performances of linear search, on CPU and on GPU (graphic processors), and also when using partial distances. Then, we propose new hash functions t solve the approximate nearest neighbours problem. The hash functions we propose are based on a selection of a few distinctive dimensions per point. For the application of near duplicate retrieval, our algorithm is more efficient than state-of-the-art algorithms. Tested on a database containing 500. 000 images, it finds similar images in less than 300ms. Eventually, we show that it fits very simply within a Bag-Of-Features approach, and it retrieves mor images than kmeans based vocabularies. In a second part, we propose several results on the problem of multi-view 3D reconstruction. We first propose a robust method to obtain the 3D reconstruction of a car from a video sequence. Our system uses the hypothesis that the car is in linear translation in order to fit a point cloud with polynomial surfaces. Then, we propose an algorithm, not dedicated to cars, that uses SIFT descriptors to obtain the 3D surface from images of an object. The descriptors correspondences are searched between input images and virtual images of the temporary object. With this method, the reconstructed surface converges to the true surface object
Lê, Thanh Vu. "Visualisation interactive 3D pour un ensemble de données géographiques de très grande taille". Pau, 2011. http://www.theses.fr/2011PAUU3005.
Pełny tekst źródłaReal-time terrain rendering remains an active area of research for a lot of modern computer based applications such as geographic information systems (GIS), interactive 3D games, flights simulators or virtual reality. The technological breakthroughs in data aquisition, coupled with recent advances in display technology have simultaneously led to substantial increases in resolution of both the Digital Elevation Models (DEM) and the various displays used to present this information. In this phD, we have presented a new out-of-core terrain visualization algorithm that achieves per-pixel accurate shading of large textured elevation maps in real-time : our first contribution is the LOD scheme which is based on a small precomputed quadtree of geometric errors, whose nodes are selected for asynchronous loading and rendering depending on a projection in screenspace of those errors. The terrain data and its color texture are manipulated by the CPU in a unified manner as a collection of raster image patches, whose dimensions depends on their screen-space occupancy ; our second contribution is a novel method to remove artifacts that appear on the border between quadtree blocks, we generate a continuous surface without needing additional mesh ; our latest contribution is an effective method adapted to our data structure for the geomorphing, it can be implemented entirely on the GPU. The presented framework exhibits several interesting features over other existing techniques : there is no mesh manipulation or mesh data structures required ; terrain geometric complexity only depends on projected elevation error views from above result in very coarse meshes), lower geometric complexity degrades terrain silhouettes but not details brought in through normal map shading, real-time rendering with support for progressive data loading ; and geometric information and color textures are similarly and efficiently handled as raster data by the CPU. Due to simplified data structures, the system is compact, CPU and GPU efficient and is simple to implement
Louis, dit Picard Stéphane Philippe Henri. "Plate-forme de communication distribuée pour les Environnements Virtuels Collaboratifs 3D à fort couplage d'activité synchrone". Lille 1, 2003. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2003/50376-2003-197.pdf.
Pełny tekst źródłaBallit, Abbass. "Design and manufacturing process optimization for prosthesis of the lower limb". Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2589.
Pełny tekst źródłaThe prosthetic socket, an essential interface element between the patient's stump and prosthetic device, is most often the place where the degree of prosthetic success is defined. It is the most critical part of the prosthesis, customized to fit with the unique residual limb of the amputee. Without a proper socket shape and fit, the prosthesis becomes uncomfortable, or even unusable, and causes pain and skin issues. The state-of-the-art prosthetic production is still missing universal numerical standards to design a socket. The current practice is expensive and relies on the manual refinements of the orthopedic technician, and the fit quality strictly correlates with his skills as well as the subjective feedback of the patient. The thesis aims to conduct a deep analysis of an optimal design of the prosthetic socket by studying and developing an alternative computer-aided design process. This process is fully based on the virtual model of the patient’s residual limb and relies on the calculation of the socket-stump interaction. A fast calculation is favorable in this case, that’s why we propose to use the Mass-Spring System (MSS) instead of the widely used FE method to model the soft tissues of the residual limb. A new configuration of the MSS model is proposed to respect the non-compressibility property of the soft tissues by adding non-linear “Corrective Springs”. The numeric model is to be generated from the scanned model of the stump. For this purpose, we propose a fusion scheme of four RGB-Depth sensors for a rapid and low-cost scan with error reduction techniques. Finally, the virtual residual limb is used in the socket designing phase. A parametric design method is proposed and investigated. The design problem is transformed into a constraint-satisfaction-problem whose constraints are derived from the inverse calculation of the stump-socket interaction. The inverse approach has been chosen to eliminate the need for expensive contact formulation. This fact leads to rapid calculations, and consequently, allows to provide real-time numerical feedback during the designing process. The validation was done by comparing the results of our system with the output of FE simulations. The system has been implemented with a user-friendly graphical interface and virtually tested and numerically validated. This system reduces the limitations of the current practices. However, a lot of works is still ahead to refine and develop the system and validate it with clinical experiments
Martinet, Aurélien. "Structuring 3D Geometry based on Symmetry and Instancing Information". Phd thesis, 2007. http://tel.archives-ouvertes.fr/tel-00379200.
Pełny tekst źródłaGUO, Jinjiang. "Contributions to objective and subjective visual quality assessment of 3d models". Thesis, 2016. http://www.theses.fr/2016LYSEI099/document.
Pełny tekst źródłaIn computer graphics realm, three-dimensional graphical data, generally represented by triangular meshes, have become commonplace, and are deployed in a variety of application processes (e.g., smoothing, compression, remeshing, simplification, rendering, etc.). However, these processes inevitably introduce artifacts, altering the visual quality of the rendered 3D data. Thus, in order to perceptually drive the processing algorithms, there is an increasing need for efficient and effective subjective and objective visual quality assessments to evaluate and predict the visual artifacts. In this thesis, we first present a comprehensive survey on different sources of artifacts in digital graphics, and current objective and subjective visual quality assessments of the artifacts. Then, we introduce a newly designed subjective quality study based on evaluations of the local visibility of geometric artifacts, in which observers were asked to mark areas of 3D meshes that contain noticeable distortions. The collected perceived distortion maps are used to illustrate several perceptual functionalities of the human visual system (HVS), and serve as ground-truth to evaluate the performances of well-known geometric attributes and metrics for predicting the local visibility of distortions. Our second study aims to evaluate the visual quality of texture mapped 3D model subjectively and objectively. To achieve these goals, we introduced 136 processed models with both geometric and texture distortions, conducted a paired-comparison subjective experiment, and invited 101 subjects to evaluate the visual qualities of the models under two rendering protocols. Driven by the collected subjective opinions, we propose two objective visual quality metrics for textured meshes, relying on the optimal combinations of geometry and texture quality measures. These proposed perceptual metrics outperform their counterparts in term of the correlation with the human judgment
Paris, Sylvain. "Extraction d'information tridimensionnelles à partir d'images -- Application à l'informatique graphique". Phd thesis, 2004. http://tel.archives-ouvertes.fr/tel-00007243.
Pełny tekst źródłaNos travaux sont centrés sur trois cas d'études qui mènent à des applications utiles. Tout d'abord, nous reconstruisons la surface d'un objet matte à partir d'une séquence d'images dont le point de vue se déplace. Nous capturons ensuite l'apparence d'un visage à partir d'une seule image et montrons comment les données récupérées sont utilisées pour synthétiser ce visage sous un nouvel éclairage. Nous terminons avec la capture de la géométrie d'une chevelure à partir de plusieurs images prises avec une caméra fixe et une lumière qui se déplace.
Nous introduisons plusieurs contributions théoriques et techniques qui améliorent aussi bien la précision que la robustesse de la capture. Des résultats illustrent ces améliorations.