Dissertations / Theses on the topic '3D visualisation and segmentation'
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1
Mao, Bo. "Visualisation and Generalisation of 3D City Models." Doctoral thesis, KTH, Geoinformatik och Geodesi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48174.
Abstract:
3D city models have been widely used in various applications such as urban planning, traffic control, disaster management etc. Efficient visualisation of 3D city models in different levels of detail (LODs) is one of the pivotal technologies to support these applications. In this thesis, a framework is proposed to visualise the 3D city models online. Then, generalisation methods are studied and tailored to create 3D city scenes in different scales dynamically. Multiple representation structures are designed to preserve the generalisation results on different level. Finally, the quality of the generalised 3D city models is evaluated by measuring the visual similarity with the original models. In the proposed online visualisation framework, City Geography Makeup Language (CityGML) is used to represent city models, then 3D scenes in Extensible 3D (X3D) are generated from the CityGML data and dynamically updated to the user side for visualisation in the Web-based Graphics Library (WebGL) supported browsers with X3D Document Object Model (X3DOM) technique. The proposed framework can be implemented at the mainstream browsers without specific plugins, but it can only support online 3D city model visualisation in small area. For visualisation of large data volumes, generalisation methods and multiple representation structures are required. To reduce the 3D data volume, various generalisation methods are investigated to increase the visualisation efficiency. On the city block level, the aggregation and typification methods are improved to simplify the 3D city models. On the street level, buildings are selected according to their visual importance and the results are stored in the indexes for dynamic visualisation. On the building level, a new LOD, shell model, is introduced. It is the exterior shell of LOD3 model, in which the objects such as windows, doors and smaller facilities are projected onto walls. On the facade level, especially for textured 3D buildings, image processing and analysis methods are employed to compress the texture. After the generalisation processes on different levels, multiple representation data structures are required to store the generalised models for dynamic visualisation. On the city block level the CityTree, a novel structure to represent group of buildings, is tested for building aggregation. According to the results, the generalised 3D city model creation time is reduced by more than 50% by using the CityTree. Meanwhile, a Minimum Spanning Tree (MST) is employed to detect the linear building group structures in the city models and they are typified with different strategies. On the building level and the street level, the visible building index is created along the road to support building selection. On facade level the TextureTree, a structure to represent building facade texture, is created based on the texture segmentation. Different generalisation strategies lead to different outcomes. It is critical to evaluate the quality of the generalised models. Visually salient features of the textured building models such as size, colour, height, etc. are employed to calculate the visual difference between the original and the generalised models. Visual similarity is the criterion in the street view level building selection. In this thesis, the visual similarity is evaluated locally and globally. On the local level, the projection area and the colour difference between the original and the generalised models are considered. On the global level, the visual features of the 3D city models are represented by Attributed Relation Graphs (ARG) and their similarity distances are calculated with the Nested Earth Mover’s Distance (NEMD) algorithm. The overall contribution of this thesis is that 3D city models are generalised in different scales (block, street, building and facade) and the results are stored in multiple representation structures for efficient dynamic visualisation, especially for online visualisation.QC 20111116
ViSuCity
2
Dufour, Alexandre. "Segmentation, suivi et visualisation d'objets biologiques en microscopie 3D par fluorescence : Approches par modèles déformables." Phd thesis, Université René Descartes - Paris V, 2007. http://tel.archives-ouvertes.fr/tel-00271191.
Abstract:
Nous nous intéressons à la détection et au suivi d'objets biologiques divers (cellules, noyaux, etc.) dans des images et séquences tri-dimensionnelles acquises en microscopie par fluorescence. L'observation de phénomènes biologiques in situ étant de plus en plus cruciale pour les experts, il est nécessaire, en plus de l'analyse quantitative, d'effectuer un rendu volumique 3D de la scène et des objets qui y évoluent. De plus, l'automatisation des techniques d'acquisition d'images requiert un haut niveau de reproductibilité des algorithmes et induit souvent des contraintes de temps de calcul que nous nous efforçons de prendre en compte.Les modèles déformables, également connus sous le nom de contours actifs, font actuellement partie des méthodes de pointe en analyse d'images pour la segmentation et le suivi d'objets grâce à leur robustesse, leur flexibilité et leur représentation à haut niveau sémantique des entités recherchées. Afin de les adapter à notre problématique, nous devons faire face à diverses difficultés. Tout d'abord, les méthodes existantes se réfèrent souvent aux variations locales d'intensité (ou gradients) de l'image pour détecter le contour des objets recherchés. Cette approche est inefficace en microscopie tridimensionnelle par fluorescence, où les gradients sont très peu prononcés selon l'axe de profondeur de l'image. Ensuite, nous devons gérer le suivi d'objets multiples susceptibles d'entrer en contact en évitant leur confusion. Enfin, nous devons mettre en place un système permettant de visualiser efficacement les contours durant leur déformation sans altérer les temps de calcul.
Dans la première partie de ce travail, nous pallions à ces problèmes en proposant un modèle de segmentation et de suivi multi-objets basé sur le formalisme des lignes de niveaux (ou level sets) et exploitant la fonctionnelle de Mumford et Shah. La méthode obtenue donne des résultats quantitatifs satisfaisants, mais ne se prête pas efficacement au rendu 3D de la scène, pour lequel nous sommes tributaires d'algorithmes dédiés à la reconstruction 3D (e.g. la méthode des "Marching Cubes"), souvent coûteux en mémoire et en temps de calcul. De plus, ces algorithmes peuvent induire des erreurs d'approximation et ainsi entraîner une mauvaise interprétation des résultats.
Dans la seconde partie, nous proposons une variation de la méthode précédente en remplaçant le formalisme des lignes de niveaux par celui des maillages triangulaires, très populaire dans le domaine de la conception assistée par ordinateur (CAO) pour leur rendu 3D rapide et précis. Cette nouvelle approche produit des résultats quantitatifs équivalents, en revanche le formalisme des maillages permet d'une part de réduire considérablement la complexité du problème et autorise d'autre part à effectuer un rendu 3D précis de la scène parallèlement au processus de segmentation, réduisant d'autant plus les temps de calculs.
Les performances des deux méthodes proposées sont d'abord évaluées puis comparées sur un jeu de données simulées reproduisant le mieux possible les caractéristiques des images réelles. Ensuite, nous nous intéressons plus particulièrement à l'évaluation de la méthode par maillages sur des données réelles, en évaluant la robustesse et la stabilité de quelques descripteurs de forme simples sur des expériences d'imagerie haut-débit. Enfin, nous présentons des applications concrètes de la méthode à des problématiques biologiques réelles, réalisées en collaboration avec d'autres équipes de l'Institut Pasteur de Corée.
3
Wang, Chen. "Large-scale 3D environmental modelling and visualisation for flood hazard warning." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/3350.
Abstract:
3D environment reconstruction has received great interest in recent years in areas such as city planning, virtual tourism and flood hazard warning. With the rapid development of computer technologies, it has become possible and necessary to develop new methodologies and techniques for real time simulation for virtual environments applications. This thesis proposes a novel dynamic simulation scheme for flood hazard warning. The work consists of three main parts: digital terrain modelling; 3D environmental reconstruction and system development; flood simulation models. The digital terrain model is constructed using real world measurement data of GIS, in terms of digital elevation data and satellite image data. An NTSP algorithm is proposed for very large data assessing, terrain modelling and visualisation. A pyramidal data arrangement structure is used for dealing with the requirements of terrain details with different resolutions. The 3D environmental reconstruction system is made up of environmental image segmentation for object identification, a new shape match method and an intelligent reconstruction system. The active contours-based multi-resolution vector-valued framework and the multi-seed region growing method are both used for extracting necessary objects from images. The shape match method is used with a template in the spatial domain for a 3D detailed small scale urban environment reconstruction. The intelligent reconstruction system is designed to recreate the whole model based on specific features of objects for large scale environment reconstruction. This study then proposes a new flood simulation scheme which is an important application of the 3D environmental reconstruction system. Two new flooding models have been developed. The first one is flood spreading model which is useful for large scale flood simulation. It consists of flooding image spatial segmentation, a water level calculation process, a standard gradient descent method for energy minimization, a flood region search and a merge process. The finite volume hydrodynamic model is built from shallow water equations which is useful for urban area flood simulation. The proposed 3D urban environment reconstruction system was tested on our simulation platform. The experiment results indicate that this method is capable of dealing with complicated and high resolution region reconstruction which is useful for many applications. When testing the 3D flood simulation system, the simulation results are very close to the real flood situation, and this method has faster speed and greater accuracy of simulating the inundation area in comparison to the conventional flood simulation models
4
Bridge, Pete. "The development and evaluation of a novel 3D radiotherapy immersive outlining tool." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/123511/1/Peter%20Bridge%20Thesis.pdf.
Abstract:
Radiotherapy target definition traditionally relies on manually drawing round the relevant anatomical structures on successive CT slices. This is a laborious process that impacts on patient throughput and can limit the adoption of more complex techniques. Although automated segmentation algorithms can create rapid volumes they lack the capacity to adapt to tumour volumes and areas of abnormal or variable anatomical structures. Such software invariably requires considerable manual input in terms of editing the outlines. In addition there is a growing desire among clinicians to be more actively involved and ensure that their clinical decision making is factored in to the generated volumes. This thesis presents a novel solution to this problem.
The primary aim of this "proof of principle" thesis is the development and evaluation of software capable of generating a mesh structure derived from a small number of points placed on a range of CT planes. This is in contrast to the traditional method of outlining that relies on a large number of points placed on successive axial CT slices. Use of a small number of points is hypothesised to require less clinician time. The software also allows the user to edit the resultant outline volumetrically with 3D modelling tools derived from animation applications. These tools enable multiple "slices" to be manually edited simultaneously while retaining a smooth and clinically relevant volume shape.
The thesis presents the development and evaluation of this new software application though a series of published works. The evaluation is drawn from a combination of qualitative research involving user focus groups and quantitative data collection relating to the clinical impact of the new paradigm.
The first published paper reports on the development of the software tool with some preliminary user evaluation highlighting recommendations for optimum use and training. Mesh generation from a small number of points placed on a range of planes was found to be a potentially rapid and effective means of target delineation, although further work was suggested to improve multi-slice volume sculpting prior to more formal pre-clinical testing.
The second paper presents qualitative data gained from Radiation Oncologist outliners relating to the clinical value of the software for accelerating clinician-directed prostate and seminal vesicle segmentation. The new tool was well-received and reported to be capable of producing very rapid and smooth volumes. This phase suffered due to time pressures experienced by the cohort and further testing of the software with a less time-poor cohort was be indicated.
The third paper was developed from the initial two phases of the study and highlighted the specific challenge of radiotherapy outlining with a lack of "gold standard" and suggests that the inherent variability mandates a constructivist approach to evaluation. This constructivist approach to variability may empower clinicians to accept variability as an inherent aspect of their practice. Furthermore, research efforts should be focussed on maximising impact of training and guidelines as well as the development of a target minimum agreed measure of intra-observer variability that educational interventions should seek to facilitate.
The final published work reported on quantitative testing of the software with a less time-pressured cohort. Student radiation therapists were tasked with outlining a bladder volume with both the new tool and the industry standard tool and found a significant (p = 0.03) time saving of 30% for bladder segmentation compared to axial-based outlining.
The new volumetric outlining paradigm is conceptually challenging and requires users to adopt a significantly different approach to generating and editing structure outlines. It also demands high levels of spatial awareness to engage with the 3D navigation tools. Given the increasing use of 3D visualisation in medicine and the non-axial image interpretation demands of MR imaging it is important that training in these techniques be embedded at pre-registration level. Future work aims to further develop this outlining tool and establish its role in editing of autosegmentation derived contour sets.
5
Verdonck, Bert. "Segmentation, mesure et visualisation des vaisseaux sanguins à partir d'angiographies 3d par résonance magnétique et tomodensitométrie helicoidale." Paris, ENST, 1996. http://www.theses.fr/1996ENST0042.
Abstract:
LE but de cette thèse était d'étudier et de développer une méthodologie générale pour détecter, reconstruire, analyser et visualiser les vaisseaux sanguins dans des images médicales en trois dimensions (3d). On utilise les modalités d'acquisition qui sont 3d, qui permettent de visualiser les vaisseaux et qui sont utilisées en routine hospitalière : l'angiographie par tomodensitométrie spirale (atdms) et par résonance magnétique (arm). Aujourd'hui le manque d'outils de segmentation adapte limite les possibilités de visualisation et de mesure sur ces images volumiques. Afin de bien traiter le problème de segmentation, on s'est penché sur la modélisation du vaisseau sanguin (les parties tubulaires). On a retenu le cylindre généralise discret avec une courbe 3d comme axe et des contours fermes 2d (polygones étoiles) orthogonaux sur l'axe. Ces contours sont définis dans un cadre de référence locale le long du vaisseau. En même temps on peut visualiser et analyser les propriétés du vaisseau dans des coupes orthogonales a l'axe. Ainsi on arrive tout de suite au modèle 3d qui est facile à visualiser et permet de faire des mesures directement. En utilisant cette modélisation, on a développé un suiveur de vaisseau, en étendant de 2d à 3d des suiveurs de routes (en imagerie aérienne ou satellitaire) et des suiveurs de vaisseaux (en angiographie classique). Le processus de poursuite ressemble à l'introduction d'un cathéter imaginaire dans le vaisseau. Cet algorithme permet d'extraire des vaisseaux d'intérêt de différentes tailles rapidement. On a étendu cette approche pour l'application spécifique de quantification précise de sténoses qui nécessite une extraction la plus précise possible. L'optimisation de la sélection entre plusieurs candidats de contour est exprimée par une fonction de cout et est effectuée par programmation dynamique. Afin de quantifier le degré de sténose précisément, on a étudié toutes les étapes du système (acquisition, segmentation et mesure) qui influencent la précision. Cette analyse a été effectuée a la fois sur le plan théorique, sur des objets synthétiques et sur des fantômes de tubes. Les tuyaux de faibles diamètres sont surtout susceptibles d'erreurs de localisation des mesures de gradient et des corrections sont proposées. Cela nous a permis de vérifier la bonne précision de nos résultats.
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Verdonck, Bert. "Segmentation, mesure et visualisation des vaisseaux sanguins à partir d'angiographies 3D par résonance magnétique et tomodensitométrie hélicoîdale /." Paris : École nationale supérieure des télécommunications, 1997. http://catalogue.bnf.fr/ark:/12148/cb36703841x.
Abstract:
Th. doct.--Signal et images--Paris--ENST, 1996.Mention parallèle de titre ou de responsabilité : Blood vessel segmentation, quantification and visualization for 3D MR and spiral CT angiography. Textes en français ou en anglais. Bibliogr. p. 151-169. Résumé en français et en anglais.
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Rekik, Wafa. "Fusion de données temporelles, ou 2D+t, et spatiales, ou 3D, pour la reconstruction de scènes 3D+t et traitement d'images sphériques : applications à la biologie cellulaire." Paris 6, 2007. http://www.theses.fr/2007PA066655.
Abstract:
Dans certaines applications en vision, nous disposons de données volumiques (3D) et des séquences planaires (2D+t). Les données 3D définissent la géométrie en trois dimensions de la scène observée. Elles comportent donc des informations purement spatiales. Les séquences 2D+t sont porteuses d'informations temporelles et partiellement spatiales puisqu'elles décrivent en deux dimensions la dynamique des objets en mouvement. La fusion de ces données permet de restituer une séquence volumique (3D+t) de la scène filmée. Ces travaux s'articulent en deux volets. Le premier volet concerne une étude méthodologique de la reconstruction 3D+t par compensation du mouvent. Nous proposons deux familles d'approches : avec ou sans modèle a priori sur les structures observées dans les données. Le modèle a priori étudiée concernent des objets de géométrie sphérique. Le second volet décrit le traitement d'image multi-dimensionnels (2D, 3D, 2D+t, 3D+t) toujours dans le contexte de forme sphérique. Nous proposons alors diverses applications comme le suivi temporel sur les séquences 2D+t, la visualisation, la segmentation des données 2D ou 3D,. . . Une application possible est donnée en imagerie biologique dans le cadre de la simulation de parois cellulaires, contexte dans lequel nous observons dans diverses modalités des objets sphéroïdes.
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Mercier, Corentin. "Geometrical modeling, simplification and visualization of brain white matter tractograms." Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT048.
Abstract:
Les données de tractographie (fibres) obtenues à partir d'IRM de diffusion sont difficiles d'utilisation. Dans cette thèse, nous proposons des méthodes et algorithmes pour la simplification, la visualisation et la manipulation de ces données. Nous introduisons une représentation multi-résolution des tractogrammes, plus rapides et avec une meilleure précision géométrique que les approches de simplification existantes. Nous explorons aussi diverses représentations géométriques et nous nous concentrons sur les approches de projections aux moindres carrés (MLS) par l'intermédiaire des surfaces algébriques d'ensemble de points (APSS), pour lesquelles nous réduisons la complexité, permettant l'utilisation de noyaux globaux pour l'analyse et la modélisation. Une technique de segmentation utilisant la représentation multi-résolution et permettant une meilleure reproductibilité que d'autres approches est ensuite présentée. Les tractogrammes pouvant être volumineux, nous introduisons un algorithme de compression exploitant la manière d'obtenir les données à partir des IRM de diffusion. La vitesse de cet algorithme permet même son utilisation pour la visualisation de données compressées, la décompression se faisant à la volée sur le GPU. Ces travaux de recherche et les résultats obtenus se situent à l'intersection de l'informatique graphique et de l'analyse de données médicales, ouvrant de nombreuses perspectivesTractography data (fibers) obtained from diffusion MRI present several challenges.In this thesis, we propose some useful methods and algorithms for simplification, visualization, and manipulation of these data.We introduce a new multi-resolution representation for tractograms, faster, and with higher geometric accuracy than existing simplification approaches.We also investigate various geometric representations and focus on moving least square (MLS) projection with algebraic point set surfaces (APSS), on which we reduce the complexity, allowing for the use of global kernels for analysis and modeling.A segmentation technique using the multi-resolution representation is presented, achieving better reproducibility than other approaches.Tractograms being massive, we also introduce a compression algorithm taking advantage of data obtention from diffusion MRI.The algorithm speed even allows for the direct use of compressed data for visualization, as it can be decompressed on-the-fly on the GPU.This research and the obtained results lie at the intersection between Computer Graphics and Medical Data Analysis, paving the way for numerous perspectives
9
Chassonnery, Pauline. "Modélisation mathématique en 3D de l'émergence de l'architecture des tissus conjonctifs." Electronic Thesis or Diss., Toulouse 3, 2023. http://www.theses.fr/2023TOU30354.
Abstract:
Cette thèse porte sur l'hypothèse que des interactions mécaniques locales simples entre un nombre limité de composants puissent régir l'émergence de l'architecture 3D des tissus biologiques. Pour explorer cette possibilité, nous développons deux modèles mathématiques. Le premier, ECMmorpho-3D, vise à reproduire un tissu conjonctif non-spécialisé réduit à la matrice extra-cellulaire, c'est-à-dire à un réseau 3D de fibres interconnectées dynamiquement. Le second, ATmorpho-3D, est obtenu par ajout de cellules sphériques apparaissant et croissant spontanément dans ce réseau de fibres afin de modéliser la morphogenèse du tissu adipeux, un tissu conjonctif spécialisé ayant une grande importance sur le plan biomédical. Pour analyser les données produites par ces deux modèles, nous construisons un outil générique permettant de visualiser en 3D des systèmes composés d'un mélange d'éléments sphériques (cellules) et de bâtonnets (fibres) et de détecter automatiquement dans de tels systèmes des amas d'objets sphériques séparés par des bâtonnets. Cet outil peut également être utilisé pour traiter des images biologiques issues de microscopie en 3D, permettant ainsi une comparaison directe entre les structures in vivo et in silico. L'étude des structures produites par le modèle ECMmorpho-3D via des simulations numériques montre que ce modèle peut générer spontanément différents types d'architectures, que nous identifions et caractérisons grâce à notre outil d'analyse. Une analyse paramétrique approfondie nous permet d'identifier une variable émergente, le nombre de liens par fibre, qui explique et, dans une certaine mesure, prédit le devenir du système modélisé. Une analyse temporelle révèle que l'échelle de temps caractéristique de ce processus d'auto-organisation est fonction de la vitesse de remodelage du réseau et que tous les systèmes suivent la même trajectoire évolutive. Enfin, nous utilisons le modèle ATmorpho-3D pour explorer l'influence de cellules sphériques sur l'organisation d'un réseau de fibres dynamique, en prenant comme référence le modèle ECMmorpho-3D. Nous montrons que le nombre de cellules influence l'alignement local des fibres mais pas l'organisation globale du réseau. Par ailleurs, les cellules s'organisent spontanément en amas entourés de feuillets de fibres, dont les caractéristiques morphologiques sont très proches de celles des structures cellulaires in vivo. De plus, la distribution des différentes morphologies d'amas cellulaires est similaire dans les systèmes in silico et in vivo. Ceci suggère que le modèle est capable de produire des morphologies réalistes non seulement à l'échelle d'un amas mais aussi à l'échelle du système entier, en reproduisant les variabilités structurelles observées dans les échantillons biologiques. Une analyse paramétrique révèle que la proportion de chaque morphologie dans un système in silico est gouvernée principalement par les capacités de remodelage du réseau de fibres, pointant le rôle essentiel des propriétés de la matrice extra-cellulaire dans l'architecture et le fonctionnement du tissu adipeux (ce qui concorde avec plusieurs constatations biologiques ainsi que des résultats antérieurs en 2D). Le fait que ces modèles mathématiques très simples puissent générer des structures réalistes corrobore notre hypothèse selon laquelle l'architecture des tissus biologiques pourrait émerger spontanément à partir d'interactions mécaniques locales entre les composants du tissu, indépendamment des phénomènes biologiques complexes se déroulant dans ce tissu. Ce travail ouvre de nombreuses perspectives quant à notre compréhension des principes fondamentaux gouvernant la manière dont l'architecture d'un tissu émerge durant l'organogenèse, est maintenue au cours de la vie et peut être affectée par diverses pathologies. Les applications potentielles vont de l'ingénierie tissulaire à la possibilité de promouvoir la régénération chez les mammifères adultesIn this thesis, we investigate whether simple local mechanical interactions between a reduced set of components could govern the emergence of the 3D architecture of biological tissues. To explore this hypothesis, we develop two mathematical models. The first one, ECMmorpho-3D, aims at reproducing a non-specialised connective tissue and is reduced to the Extra-Cellular Matrix (ECM) component, that is a 3D dynamically connected fibre network. The second, ATmorpho-3D, is built by adding to this network spherical cells which spontaneously appear and grow in order to mimic the morphogenesis of Adipose Tissue (AT), a specialised connective tissue with major biomedical importance. We then construct a unified analysis framework to visualise, segment and quantitatively characterise the fibrous and cellular structures produced by our two models. It constitutes a generic tool for the 3D visualisation of systems composed of a mixture of spherical (cells) and rod-like (fibres) elements and for the automatic detection of in such systems of clusters of spherical objects separated by rod-like elements. This tool is also applicable to biological 3D microscopy images, enabling a comparison between in vivo and in silico structures. We study the structures produced by the model ECMmorpho-3D by performing numerical simula- tions. We show that this model is able to spontaneously generate different types of architectures, which we identify and characterise using our analysis framework. An in-depth parametric analysis lead us to identify an intermediate emerging variable, the number of crosslinks per fibre, which explains and partly predicts the fate of the modelled system. A temporal analysis reveals that the characteristic time-scale of the organisation process is a function of the network remodelling speed, and that all systems follow the same, unique evolutionary pathway. Finally, we use the model ATmorpho-3D to explore the influence of round cells over the organisation of a fibre network, taking as reference the model ECMmorpho-3D. We show that the number of cells can influence the local alignment of the fibres but not the global organisation of the network. On the other hand, the cells inside the network spontaneously organise into clusters with realistic morphological features very close to those of in vivo structures, surrounded by sheet-like fibre bundles. Moreover, the distribution of the different morphological types of clusters is similar in in silico and in vivo systems, suggesting that the model is able to produce realistic morphologies not only on the scale of one cluster but also on the scale of the whole system, reproducing the structural variability observed in biological samples. A parametric analysis reveals that the proportion in which each morphology is present in an in silico system is governed mainly by the remodelling characteristic of the fibres, pointing to the essential role of the ECM properties in AT architecture and function (in agreement with several biological results and previous 2D findings). The fact that these very simple mathematical models can produce realistic structures supports our hypothesis that biological tissues architecture could emerge spontaneously from local mechanical inter- actions between the tissue components, independently of the complex biological phenomena taking place around them. This opens many perspectives regarding our understanding of the fundamental principles governing how biological tissue architecture emerges during organogenesis, is maintained throughout life and can be affected by various pathological conditions. Potential applications range from tissue engineering to therapeutic treatment inducing regeneration in adult mammals
10
Robert, Bruno. "Echographie Tridimensionnelle." Phd thesis, Télécom ParisTech, 1999. http://tel.archives-ouvertes.fr/tel-00005697.
Abstract:
Avec les échographes classiques, le médecin explore un volume à partir de plans de coupe. Il intègre ensuite les informations volumiques en coordonnant les images obtenues et les positions de la sonde. Les techniques d'échographie tridimensionnelle récupèrent directement les données volumiques, qui peuvent ensuite être exploitées de manière plus ou moins automatique. L'objectif de cette thèse est de permettre l'évaluation clinique des techniques ultrasonores tridimensionnelles, notamment en ce qui concerne l'exploration de la région thyroïdienne. Pour ce faire, nous avons développé un système qui repère les mouvements de la sonde échographique pendant que l'opérateur explore le volume étudié. Deux systèmes de repérages ont été testés : un bras mécanique et un capteur électromagnétique. Dans une première étape, nous avons étudié les problèmes de calibrage et la précision du repérage dans les conditions d'utilisation. Les caractéristiques des données ultrasonores rendent le problème de la visualisation des données tridimensionnelles particulièrement difficile. Nous proposons une méthode interactive pour obtenir des images tridimensionnelles réalistes et estimer le volume des structures étudiées. Les images obtenues facilitent alors l'échange d'informations entre l'opérateur et le chirurgien ou le patient. Nous présentons enfin deux méthodes de segmentation pour améliorer la visualisation des données dans deux situations précises. En ce qui concerne la région thyroïdienne, la segmentation semi-automatique de la carotide facilite la localisation des adénomes. En obstétrique, un algorithme de détection des parois la cavité utérine permet d'améliorer la visualisation du foetus.
11
Cinquin, Philippe. "Application des fonctions-spline au traitement d'images numériques." Habilitation à diriger des recherches, Grenoble 1, 1987. http://tel.archives-ouvertes.fr/tel-00325721.
Abstract:
Étude portant sur la modélisation d'images a traiter. Application des fonctions spline. Diverses techniques d'approximation sont mises en œuvre et des algorithmes spécifiques sont développés pour s'adapter au volume important des données. L'intérêt de cette représentation confirmée est illustré sur trois exemples d'origine médicale
12
Ärleryd, Sebastian. "Realtime Virtual 3D Image of Kidney Using Pre-Operative CT Image for Geometry and Realtime US-Image for Tracking." Thesis, Uppsala universitet, Avdelningen för visuell information och interaktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-234991.
Abstract:
In this thesis a method is presented to provide a 3D visualization of the human kidney and surrounding tissue during kidney surgery. The method takes advantage of the high detail of 3D X-Ray Computed Tomography (CT) and the high time resolution of Ultrasonography (US). By extracting the geometry from a single preoperative CT scan and animating the kidney by tracking its position in real time US images, a 3D visualization of the surgical volume can be created. The first part of the project consisted of building an imaging phantom as a simplified model of the human body around the kidney. It consists of three parts: the shell part representing surrounding tissue, the kidney part representing the kidney soft tissue and a kidney stone part embedded in the kidney part. The shell and soft tissue kidney parts was cast with a mixture of the synthetic polymer Polyvinyl Alchohol (PVA) and water. The kidney stone part was cast with epoxy glue. All three parts where designed to look like human tissue in CT and US images. The method is a pipeline of stages that starts with acquiring the CT image as a 3D matrix of intensity values. This matrix is then segmented, resulting in separate polygonal 3D models for the three phantom parts. A scan of the model is then performed using US, producing a sequence of US images. A computer program extracts easily recognizable image feature points from the images in the sequence. Knowing the spatial position and orientation of a new US image in which these features can be found again allows the position of the kidney to be calculated. The presented method is realized as a proof of concept implementation of the pipeline. The implementation displays an interactive visualization where the kidney is positioned according to a user-selected US image scanned for image features. Using the proof of concept implementation as a guide, the accuracy of the proposed method is estimated to be bounded by the acquired image data. For high resolution CT and US images, the accuracy can be in the order of a few millimeters.
13
Hult, Roger. "Segmentation and Visualisation of Human Brain Structures." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3567.
14
Kanafani, Qosaï. "Compression et visualisation d'images médicales par segmentation." Paris 13, 2003. http://www.theses.fr/2003PA132017.
Abstract:
Dans cette thèse, nous étudions les images médicales obtenues par IRM et par CT. Le premier aspect considéré est l'amélioration de la qualité de ces images. Et le deuxième aspect est le choix de méthodes de segmentation adaptées aux images médicales. Nous avons opté pour la segmentation stochastique basée sur un modèle de mélange. La compression du volume de donnée 3D est aussi étudiée. Une méthode de compression simple et efficace est proposée et évaluée au moyen de critères de qualité subjective et objective. Les résultats obtenus sont encourageants et montrent encore une fois que la réticence quand à l'utilisation des méthodes de compression avec perte dans le cas des images médicales n'est pas trés justifiée. Il s'agit dans cette thèse de répondre à des besoins spécifiques en apportant des solutions originales qui tiennent compte de l'existant, de la nature des images et de leur usage. Nous avons aussi insisté sur les critères de temps de calcul, de flexibilité et de fiabilité.
15
Maselino, Prince. "Load balancing for parallel 3D visualisation." Thesis, University of Westminster, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442101.
16
Boyle, John. "Using 3D graphics for database visualisation." Thesis, University of Aberdeen, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307951.
Abstract:
The upsurge in the number of casual users and the general acceptance of computer technology has shown that the principal driving force in software engineering is shifting from functionality to usability. It has also become evident that the desktop metaphor and its whole related genre do not provide the modern interface designer with the expressive power that is needed. Nowhere is a new approach more needed than in interfaces for databases. Previous studies in interface design for database management systems have attempted to use solely the desktop metaphor. We have used three dimensional graphical techniques to construct an interface, called Amaze for our object oriented database P/FDM. Interactive animated 3D graphics have been embedded inside a standard menu driven framework. Using 3D graphics new metaphors have been developed to aid the user interaction. Our development has taken a modular approach, which allowed us to develop a number of different visualisations for query construction, the structure of the database and result representation. It is possible to view the data using a number of multimodal displays (a number of customised multimodal displays have been built). Amaze has been used on a variety of different data sets (including a protein structure database, a personnel database and an antibody database). These databases differ greatly in size and complexity of their semantics. The work discussed in this thesis suggests an alternative approach to user interface design for database systems, it introduces the idea of Database Visualisation and suggests novel mechanisms for computer interaction using 3D graphics.
17
Mao, Bo. "Visualisation and Generalisation of 3D City Models." Licentiate thesis, KTH, Geoinformatics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-24345.
Abstract:
3D city models have been widely used in different applications such as urban planning, traffic control, disaster management etc. Effective visualisation of 3D city models in various scales is one of the pivotal techniques to implement these applications. In this thesis, a framework is proposed to visualise the 3D city models both online and offline using City Geography Makeup Language (CityGML) and Extensible 3D (X3D) to represent and present the models. Then, generalisation methods are studied and tailored to create 3D city scenes in multi-scale dynamically. Finally, the quality of generalised 3D city models is evaluated by measuring the visual similarity from the original models.
In the proposed visualisation framework, 3D city models are stored in CityGML format which supports both geometric and semantic information. These CityGML files are parsed to create 3D scenes and be visualised with existing 3D standard. Because the input and output in the framework are all standardised, it is possible to integrate city models from different sources and visualise them through the different viewers.
Considering the complexity of the city objects, generalisation methods are studied to simplify the city models and increase the visualisation efficiency. In this thesis, the aggregation and typification methods are improved to simplify the 3D city models.
Multiple representation data structures are required to store the generalisation information for dynamic visualisation. One of these is the CityTree, a novel structure to represent building group, which is tested for building aggregation. Meanwhile, Minimum Spanning Tree (MST) is employed to detect the linear building group structures in the city models and they are typified with different strategies. According to the experiments results, by using the CityTree, the generalised 3D city model creation time is reduced by more than 50%.
Different generalisation strategies lead to different outcomes. It is important to evaluate the quality of the generalised models. In this thesis a new evaluation method is proposed: visual features of the 3D city models are represented by Attributed Relation Graph (ARG) and their similarity distances are calculated with Nested Earth Mover’s Distance (NEMD) algorithm. The calculation results and user survey show that the ARG and NEMD methods can reflect the visual similarity between generalised city models and the original ones.
QC 20100923
ViSuCity Project
18
Tang, Hui. "Méthodologies de visualisation 3D en imagerie médicale." Phd thesis, Université Rennes 1, 2008. http://tel.archives-ouvertes.fr/tel-00355629.
Abstract:
Ce mémoire de Thèse se focalise sur certains des problèmes non résolus en visualisation scientifique. Plus particulièrement nous avons pris une problématique médicale bien spécifique, la chirurgie conservatrice des tumeurs rénales, comme cadre applicatif pour l'élaboration de nouvelles solutions incluant des techniques de recalage de données, de segmentation et de visualisation 3D.L'uroscan fournit 3 à 4 volumes présentant une information complémentaire sur l'anatomie rénale. La première étape consiste à mettre en correspondance ces différents volumes par une technique de recalage rigide du volume rénal basée sur la maximisation locale de l'information mutuelle.
L'idée principale de ce mémoire de Thèse est de proposer une visualisation de l'anatomie rénale directement à partir de ces données fusionnées. Pour cela, une technique de classification statistique des données basée sur une modélisation de la distribution des valeurs par un mélange de Gaussiennes incluant une information spatiale a été développée. Différentes techniques de visualisation 3D ont ensuite été adaptées à la représentation de cette information et comparées entre-elles.
Les techniques de représentation de surfaces peuvent être accélérées par des procédures de simplifications de maillages. Dans ce cadre, nous avons proposé deux métriques de description de la surface basées sur les moments géométriques et pouvant être incluses dans une telle procédure.
Ces différentes solutions, même si elles ont été développées dans le cadre de la représentation des structures anatomiques rénale, sont suffisamment génériques pour être utilisées ou adaptées à d'autres organes ou à d'autres applications médicales.
19
Martin, Ian John. "Multi-spectral image segmentation and compression." Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343123.
20
Algharabat, Raed S. "Modelling 3D product visualisation for the online retailer." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4525.
Abstract:
This research aims to explain the process that previous researchers have discussed concerning the consumer virtual experience, using three-dimensional (3D) product visualisations, within online retailers. In addition, this research aims to identify the main advantages of using 3D product visualisation in comparison to two-dimensional (2D) static pictures within online retailers. Moreover, using the online Stimulus-Organism-Responses (S-O-R) paradigm, this research aims to model the effect of 3D product visualisation on consumers’ perception and responses towards the online retailer environment. Given that the appearance of the notion of telepresence or presence and their implications on the online retailer, many scholars attempt to build and develop models that can suit these notions online. However, this thesis argues that the notion of 3D telepresence is not the proper terminology to be used within the online retail context and therefore, this research raises the following question “how do consumers perceive 3D product virtualisation (telepresence) compared with 3D product authenticity on online retailers’ websites?” The effects of 3D product visualisation and 2D static pictures have been raised during the past decade to determine which is better for the online consumers. Marketers and information system scholars started wondering about the best device that can generate hedonic and utilitarian values for the consumers. To investigate the main impact of 3D product visualisation and 2D static pictures on hedonic and utilitarian values, this research raises the following questions: How do consumers perceive 3D hedonic values compared with 2D hedonic values on online retailers’ website? How do consumers perceive 3D product visualisation utilitarian values compared with 2D utilitarian values on online retailers’ website? This thesis, based on the previous literature in interactivity and vividness, narrowed down the 3D authenticity antecedents to the control and animated colour constructs. Moreover, to determine the effect of the progressive levels of control and animated colour constructs on the 3D authenticity construct, it raises the following research question: How do different levels of 3D control and animated colours influence 3D authenticity? To determine the effects of the progressive levels of 3D hedonic and utilitarian values on behavioural intention construct, this thesis raises the following research question: How do different levels of 3D hedonic and utilitarian levels influence behavioural intentions? Based on the online S-O-R framework, previous studies investigate the impact of the whole website e-retail environment (many stimuli) on consumers’ responses. Yet, this is the first study that is using one stimulus, namely 3D laptop product visualisation to investigate its impacts on consumers’ perceptions and responses using the online S-OR paradigm. Therefore, this thesis raises the following research question: How do control, animated colours, 3D authenticity, hedonic and utilitarian values affect consumers’ behavioural intention? The results reveal significant differences between 3D telepresence and 3D authenticity constructs. 3D telepresence involves an illusion or a sense of being transported to another place, whereas 3D authenticity refers to the ability to imagine a virtual object as real. The 3D authenticity construct is more significant in simulating an online retailer’s products. The proposed online S-O-R conceptual model achieves acceptable fit and the hypothesised paths are all valid. This research adds to the marketing literature the notion of 3D authenticity and contributes a valid scale to measure that new variable. Moreover, it is the first study that connects and uses the antecedents of 3D authenticity (S), control and animated colours, to investigate their impact on 3D authenticity, hedonic and utilitarian values (O), and the impact of the Organism constructs (O) on behavioural intention (R). Furthermore, the final framework considers the first framework that has studied the impact of one stimulus using the online S-O-R framework on an electronic retailer website environment. Indeed, to the best of the researcher’s knowledge, this is the first study that uses a UK sample to investigate the effects of an authentic 3D product visualisation in an electronic e-retailing industry (i.e., laptops).
21
Ottoson, Patrik. "Geographic Indexing and Data Management for 3D-Visualisation." Doctoral thesis, Stockholm : Tekniska högsk, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3235.
22
Norberg, Amanda, and Elliot Rask. "3D visualisation of breast reconstruction using Microsoft HoloLens." Thesis, Uppsala universitet, Signaler och System, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-367277.
Abstract:
The purpose of the project is to create a Mixed Reality (MR) application for the 3D visualisation of the result of a breast reconstruction surgery. The application is to be used before surgery to facilitate communication between patient an surgeon about the expected result. To this purpose Microsoft HoloLens is used, which is a pair of Mixed Reality (MR) glasses developed and manufactured by Microsoft that has a self-contained, holographic rendering computer. For the development of the MR application on the Hololens, MixedRealityToolkit-Unity is used which is a Unity-based toolkit available. The goal of the application is that the user can scan a torso of a patient, render a hologram of the torso and attach to it a prefabricated breast which possibly follows the patient's specification. To prepare a prefabricated breast, a 3D model of the breast is first created in the 3D modelling software Blender. It then gets its texture from a picture taken with the HoloLens camera. The picture is cropped to better fit the model and uploaded as a 2D texture which is then attached to the prefabricated breast, which is imported into Unity. To scan objects, the HoloLens’s operating system feature Surface Observer is used. The resulting mesh from the observer is cropped using a virtual cube, scaled, moved and rotated by the user. The cropped mesh is then smoothed using the Humphrey's Classes smoothing algorithm. To fuse the smoothed mesh with the prefabricated breast model, the Unity components: Colliders and Transforms are used. On a collision the breast's transform parent is set to the mesh’s transform, making the objects transforms behave depending on each other. The MR application has been developed and evaluated. The evaluation results show that the goal has been achieved successfully. The project demonstrates that the Microsoft HoloLens is well suited for developing such medical applications as breast reconstructive surgery visualisations. It can possibly be extended to other surgeries such as showing on a patient’s body how the scar will look after a heart surgery, or a cesarean section.
23
Muñoz, Álvaro Aranda. "Comparing 3D interfaces of virtual factories : an iconic 3D interface against an abstract 3D visualisation." Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4115.
Abstract:
Context. 3D visualisations are highly demanded in different industries such as virtual factories. However, the benefits that 3D representations can bring to this industry have not been fully explored, being most of the representations either photorealistic or presenting abstract visualisations. Objectives. This thesis explores and compares two prototypes that present a visualisation of the process state of a factory. The first prototype presents a generic interface in which primitive 3D shapes convey the information of the factory status. The second prototype is complemented with specific and iconic 3D models of the factory that help the users associating the conveyed information to the factory flow. The motivation behind this dissertation is that the type of generic interface presented can lead to more reusable interfaces in the future. Methods. For the creation and development of the prototypes, the user-centered design process was followed in which the designs are iterated with users of the factory. Based on the two prototypes, a usability evaluation is conducted to analyse the perceived usability and the usability performance. This is complemented with post-interviews with all the participants. The results are presented attending to the triangulation methodology to support the strength of the qualitative findings. Conclusions. The results show that both interfaces are perceived as highly usable. However, the 3D iconic interface seemed to help the users more in depicting a better mental model of the factory flow, helping the users to complete most of the tasks with faster times.This thesis explores and compares two prototypes that present a visualisation of the process state of a factory. The first prototype presents a generic interface in which primitive 3D shapes convey the information of the factory status. The second prototype is complemented with specific and iconic 3D models of the factory that help the users associating the conveyed information to the factory flow. The motivation behind this dissertation is that the type of generic interface presented can lead to more reusable interfaces in the future.
24
Taylor, Ian. "'Dynamic scaling for three-dimensional information visualisation'." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324478.
25
Green, Damian Alan. "Stratigraphic visualisation for archaeological investigation." Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/2168.
Abstract:
The principal objective of archaeology is to reconstruct in all possible ways the life of a community at a specific physical location throughout a specific time period. Distinctly separate layers of soil provide evidence for a specific time period. Discovered artefacts are most frequently used to date the layer. An artefact taken out of context is virtually worthless; hence the correct registration of the layer in which they were uncovered is of great importance. The most popular way to record temporal relationships between stratigraphic layers is through the use of the 2D Harris Matrix method. Without accurate 3D spatial recording of the layers, it is difficult if not impossible, to form new stratigraphic correspondences or correlations. New techniques for archaeological recording, reconstruction, visualisation and interpretation in 3D space are described in these works and as a result software has been developed. Within the developed software system, legacy stratigraphy data, reconstructed from archaeological notebooks can be integrated with contemporary photogrammetric models and theodolite point data representations to provide as comprehensive a reconstruction as possible. The new methods developed from this research have the capability to illustrate the progression of the excavation over time. This is made possible after the entry of only two or more strata. Sophisticated, yet easy-to-use tools allow the navigation of the entire site in 3D. Through the use of an animation-bar it is possible to replay through time both the excavation period and the occupation period, that is to say the various time periods in antiquity when human beings occupied these locations. The lack of complete and consistent recording of the soil layers was an issue that proved to be an obstacle for complete reconstruction during the development of these methods. A lack of worldwide archaeological consensus on the methods of stratigraphic recording inhibited development of a universal scientific tool. As a result, new recording methods are suggested to allow more scientific stratigraphic reconstruction.
26
Elghoul, Esma. "Segmentation de maillages 3D par l'exemple." Thesis, Paris, ENST, 2014. http://www.theses.fr/2014ENST0051/document.
Abstract:
Cette thèse présente une méthode de segmentation de modèles 3D en parties significatives ou fonctionnelles. La segmentation s’effectue par "transfert" d’une segmentation exemple : la segmentation d’un modèle est calculée en transférant les segments d’une segmentation exemple d’un objet appartenant à la même classe de modèles 3D. Pour ce faire, nous avons adapté et étendu la méthode de segmentation par les marches aléatoires et transformé notre problème en un problème de localisation et mise en correspondance de faces germes. Notre méthode comporte quatre étapes fondamentales : la mise en correspondance entre le modèle exemple et le modèle cible, la localisation automatique de germes sur le modèle cible pour initialiser les régions, le calcul des segments du modèle cible et l’amélioration de leurs frontières. En constatant que les critères de similarité diffèrent selon que les objets sont de type rigide (chaises, avions,…) ou de type articulé (humains, quadrupèdes,…), nous décomposons notre approche en deux. La première dédiée aux objets rigides, où la mise en correspondance est basée sur le calcul des transformations rigides afin d’aligner au mieux les parties significatives des deux objets comparés. La deuxième dédiée aux modèles articulés, où la mise en correspondance des parties fonctionnelles, présentant des variations de poses plus importantes, est basée sur des squelettes calculés via des diagrammes de Reeb. Nous montrons à travers des évaluations qualitatives et quantitatives que notre méthode obtient des résultats meilleurs que les techniques de segmentation individuelle et comparables aux techniques de co-segmentation avec un temps de calcul nettement inférieurIn this dissertation, we present a new method to segment 3D models into their functional parts. The segmentation is performed by a transfer approach: a semantic-oriented segmentation of an object is calculated using a pre-segmented example model from the same class (chairs, humans, etc.). To this end, we adapted and extended the random walk segmentation method which allowed us to transform our problem into a problem of locating and matching seed faces. Our method consists of four fundamental steps: establishing correspondences between the example and the target model, localizing seeds to initialize regions in the target model, computing the segments and refining their boundaries in the target model. We decomposed our approach in two, taking into account similarity criteria which differ regarding the object type (rigid vs. articulated). The first approach is dedicated to rigid objects (chairs, airplanes, etc.), where the matching is based on rigid transformations to determine the best alignment between the functional parts of the compared objects. The second one focused on articulated objects (humans, quadrupeds, etc.), where coarse topological shape attributes are used in a skeleton-based approach to cover larger pose variations when computing correspondences between functional parts. We show through qualitative and quantitative evaluations that our method improves upon individual segmentation techniques and obtains results that are close to the co-segmentation techniques results with an important calculation time reduction
27
Elghoul, Esma. "Segmentation de maillages 3D par l'exemple." Electronic Thesis or Diss., Paris, ENST, 2014. http://www.theses.fr/2014ENST0051.
Abstract:
Cette thèse présente une méthode de segmentation de modèles 3D en parties significatives ou fonctionnelles. La segmentation s’effectue par "transfert" d’une segmentation exemple : la segmentation d’un modèle est calculée en transférant les segments d’une segmentation exemple d’un objet appartenant à la même classe de modèles 3D. Pour ce faire, nous avons adapté et étendu la méthode de segmentation par les marches aléatoires et transformé notre problème en un problème de localisation et mise en correspondance de faces germes. Notre méthode comporte quatre étapes fondamentales : la mise en correspondance entre le modèle exemple et le modèle cible, la localisation automatique de germes sur le modèle cible pour initialiser les régions, le calcul des segments du modèle cible et l’amélioration de leurs frontières. En constatant que les critères de similarité diffèrent selon que les objets sont de type rigide (chaises, avions,…) ou de type articulé (humains, quadrupèdes,…), nous décomposons notre approche en deux. La première dédiée aux objets rigides, où la mise en correspondance est basée sur le calcul des transformations rigides afin d’aligner au mieux les parties significatives des deux objets comparés. La deuxième dédiée aux modèles articulés, où la mise en correspondance des parties fonctionnelles, présentant des variations de poses plus importantes, est basée sur des squelettes calculés via des diagrammes de Reeb. Nous montrons à travers des évaluations qualitatives et quantitatives que notre méthode obtient des résultats meilleurs que les techniques de segmentation individuelle et comparables aux techniques de co-segmentation avec un temps de calcul nettement inférieurIn this dissertation, we present a new method to segment 3D models into their functional parts. The segmentation is performed by a transfer approach: a semantic-oriented segmentation of an object is calculated using a pre-segmented example model from the same class (chairs, humans, etc.). To this end, we adapted and extended the random walk segmentation method which allowed us to transform our problem into a problem of locating and matching seed faces. Our method consists of four fundamental steps: establishing correspondences between the example and the target model, localizing seeds to initialize regions in the target model, computing the segments and refining their boundaries in the target model. We decomposed our approach in two, taking into account similarity criteria which differ regarding the object type (rigid vs. articulated). The first approach is dedicated to rigid objects (chairs, airplanes, etc.), where the matching is based on rigid transformations to determine the best alignment between the functional parts of the compared objects. The second one focused on articulated objects (humans, quadrupeds, etc.), where coarse topological shape attributes are used in a skeleton-based approach to cover larger pose variations when computing correspondences between functional parts. We show through qualitative and quantitative evaluations that our method improves upon individual segmentation techniques and obtains results that are close to the co-segmentation techniques results with an important calculation time reduction
28
Janols, Henrik. "Communicating long-span timber structures with 3D computer visualisation /." Luleå, 2005. http://epubl.luth.se/1402-1757/2005/30.
29
Hayat, Khizar. "Visualisation 3D adaptée par insertion synchronisée de données cachées." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2009. http://tel.archives-ouvertes.fr/tel-00400762.
Abstract:
L'objectif principal de ces travaux de thèse est d'unifier différentes informations 2D et 3D afin de réaliser une visualisation adaptée dans un environnement client/serveur hétérogène en termes de réseau, de traitement et de ressources mémoire. Dans ce contexte, nous avons exploité la nature multi-résolution de la transformée en ondelettes discrètes (TOD) du codeur JPEG2000. L'unification des données est réalisée par insertion aveugle, synchrone ou partiellement synchrone, des données cachées dans le domaine des ondelettes. Une visualisation 3D classique nécessite au moins deux types de données : une image 2D d'intensité, appelé texture, et une forme 3D pouvant être représentée par une image, un modèle 3D ombré ou un maillage de points. Ce type d'image, parfois également appelé carte de profondeur est une image dans laquelle la valeur des pixels reflète la distance du capteur à la surface par imagerie. La texture est une image 2D couleur qui est apposée sur le modèle 3D après triangulation. Au niveau de l'insertion des données cachées, la carte de profondeur est d'abord transformée dans le domaine des ondelettes tandis que la texture est insérée dans le codeur JPEG2000. Le processus de codage JPEG2000 de la texture est interrompue, et les coefficients 3D sont insérés dans la totalité ou dans un sous-ensemble des sous-bandes de la texture. Les données sont re-intégrées dans le codeur standard de JPEG2000 à l'endroit où l'interruption a été faite. Le fichier résultant peut alors être envoyé à travers tous types de canal de communication comme un autre fichier standard issu du codeur JPEG2000. Les différents niveaux de résolution et le caractère synchronisé de nos algorithmes permettent une visualisation en 3D, même avec peu de sous-bandes de résolution suite à un transfert partiel ou retardé. La méthode permet ainsi d'effectuer une visualisation à partir uniquement d'une fraction des données. Dans ce cas nous remplaçons par des zéros les coefficients des sous-bandes manquantes. La première phase de ce travail a concerné l'imperceptibilité; c'est la raison pour laquelle l'insertion a été réalisée dans les bits de poids plus faibles. La deuxième phase de ces travaux a concerné la robustesse, c'est pourquoi une stratégie d'insertion par étalement de spectres a été utilisée. Au cours de la seconde phase, l'imperceptibilité n'a pas été complètement ignorée, du fait que l'insertion des données est effaçable après l'extraction. Les deux applications principales sont la visualisation 3D de modèles numériques de terrains et de visages. Dans la troisième et dernière phase de ces travaux de thèse, nous avons élargi le problème en essayant de prendre en compte le problème d'assemblage de dalles de niveaux de résolutions différentes sans soudure apparente. Ceci a eté assuré par des fonctions de lissage dans le domaine des ondelettes.
30
Mahieddine, Mohammed. "Modélisation, visualisation et animation d'objets 3D : Approche orientée objets." nice, 1991. http://www.theses.fr/1991NICE4496.
Abstract:
L'objectif de cette thèse est d'étudier l'application de l'approche orientée objets pour la modélisation, la visualisation et l'animation d'objets graphiques en 3 dimensions. Une première phase de cette étude a consiste en la construction d'une extension orientée objets de standards graphiques existants. Pour la construction du graphe d'héritage des classes, une méthode nouvelle est présentée qui consiste à utiliser a la fois l'héritage comportemental et l'héritage implémentationnel. Une extension orientée objets des systèmes core et cgi est présentée pour illustrer ces idées. Une étude exhaustive des méthodes de modélisation des courbes, des surfaces et des solides a permis de montrer l'intérêt des classes et de l'héritage pour réduire la difficulté de confection d'un logiciel de modélisation d'objets géométriques 3d. En ce qui concerne la visualisation des objets, nous montrons les avantages et les limites de l'approche orientée objets pour l'élimination des faces cachées, la manipulation des couleurs et le rendu réaliste (lancer de rayons). Nous montrons ensuite comment décrire l'animation des objets avec les concepts de classes et d'héritage et nous comparons cette approche avec celle des acteurs. La validation de cette approche a consiste à réaliser une application d'animation de robots articules en c++ sous x window. Ce travail démontre que la méthodologie orientée objets permet d'avoir une approche unifiée a la fois pour la modélisation géométrique, la visualisation des objets graphiques et pour leur animation
31
Rozendaal, Ross. "Interactive visualisation using 3D graphics : an archaeological case study." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/4980.
Abstract:
Bibliography: leaves 82-84.The methods of displaying data from archaeological surveys are of considerable importance in representing realistic impressions of archaeological sites that few people are able to visit. In many cases, further study of a site is not possible at the location of the site. This would require that the surveyed data of the site be displayed in such a way as to be accurate and realistic as well as including interactive tools, enabling further studies. Traditional displays of archaeological data have been either in textual form or in the conventional hardcopy form of maps and drawings. With the advent of computers and computer graphics alternative methods of displaying the data have become possible. 3D graphics have become an important method of displaying archaeological data. In 1995 and 1996 the Department of Geomatics at the University of Cape Town participated in the survey of the 3.6 million year old hominid footprints in Tanzania. The survey was required for the documentation and study of the footprints. In order to facilitate this in 3D graphics, software packages that allowed user interactive tools to be included in the display had to be investigated. Methods of displaying the data also had to be investigated. Java3D was selected to create the 3D models and user interactive tools that included measurement tools, gradient tools and profile tools. These tools were created for the Laetoli footprints but were applicable in other archaeological displays as well.
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Taylor, Simon. "3D visualisation of the laetoli footprints on the internet." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/4979.
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Kabil, Alexandre. "CyberCOP 3D : visualisation 3D interactive et collaborative de l'état de sécurité d'un système informatique." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2019. http://www.theses.fr/2019IMTA0166.
Abstract:
L’objectif de la thèse était d’étudier l’utilisation d’Environnements Virtuels Collaboratifs (EVC) pour l’analyse de l’état de sécuritéde systèmes informatiques, aussi appelée la Cyber Situational Awareness (CSA). Après avoir étudié les modèles et outils de la CSA, nous avons pu visiter les Security Operations Center (SOCs) de quatre partenaires industriels de la Chaire Cyber CNI, afin de mieux cerner les besoins et attentes des cyber analystes. Ces visites ont été effectuées dans le cadre d’un protocole de l’analyse de l’activité collaborative et nous ont permises de proposer un modèle, le CyberCOP 3D. En nous basant sur notre modèle ainsi que sur une modélisation du rançongiciel WannaCry, nous avons développé un EVC pour la cybersécurité ainsi qu’un moteur de scénarisation simplifié permettant à des utilisateurs de concevoir leurs propres scénarios d’analyse d’alertes. Nous avons effectué une évaluation de l’utilisabilité d’un environnement virtuel pour l’analyse d’alertes auprès d’utilisateurs non-experts en cybersécuritéThe aim of this thesis was to study the use of Collaborative Virtual Environments (CVE) for the analysis of the state of security of computer systems, also called Cyber Situational Awareness (CSA). After studying CSA’s models and tools, we have had the opportunity to visit the Security Operations Centers (SOCs) of four industrial partners of the CyberCNI chair, in order to better understand the needs and expectations of cyber analysts. These visits were made as part of a collaborative activity analysis protocol and have allowed us to propose a model, the 3D Cyber-COP. Based on this model and a model of the WannaCry ransomware, we have developed a CVE and a simplified scenario engine that allows users to design their own alert analysis scenarios. We have also performed a usability evaluation of a virtual environment for alert analysis, with a panel of novice users
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Chen, Yifu. "Deep learning for visual semantic segmentation." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS200.
Abstract:
Dans cette thèse, nous nous intéressons à la segmentation sémantique visuelle, une des tâches de haut niveau qui ouvre la voie à une compréhension complète des scènes. Plus précisément, elle requiert une compréhension sémantique au niveau du pixel. Avec le succès de l’apprentissage approfondi de ces dernières années, les problèmes de segmentation sémantique sont abordés en utilisant des architectures profondes. Dans la première partie, nous nous concentrons sur la construction d’une fonction de coût plus appropriée pour la segmentation sémantique. En particulier, nous définissons une nouvelle fonction de coût basé sur un réseau de neurone de détection de contour sémantique. Cette fonction de coût impose des prédictions au niveau du pixel cohérentes avec les informa- tions de contour sémantique de la vérité terrain, et conduit donc à des résultats de segmentation mieux délimités. Dans la deuxième partie, nous abordons une autre question importante, à savoir l’apprentissage de modèle de segmentation avec peu de données annotées. Pour cela, nous proposons une nouvelle méthode d’attribution qui identifie les régions les plus importantes dans une image considérée par les réseaux de classification. Nous intégrons ensuite notre méthode d’attribution dans un contexte de segmentation faiblement supervisé. Les modèles de segmentation sémantique sont ainsi entraînés avec des données étiquetées au niveau de l’image uniquement, facile à collecter en grande quantité. Tous les modèles proposés dans cette thèse sont évalués expérimentalement de manière approfondie sur plusieurs ensembles de données et les résultats sont compétitifs avec ceux de la littératureIn this thesis, we are interested in Visual Semantic Segmentation, one of the high-level task that paves the way towards complete scene understanding. Specifically, it requires a semantic understanding at the pixel level. With the success of deep learning in recent years, semantic segmentation problems are being tackled using deep architectures. In the first part, we focus on the construction of a more appropriate loss function for semantic segmentation. More precisely, we define a novel loss function by employing a semantic edge detection network. This loss imposes pixel-level predictions to be consistent with the ground truth semantic edge information, and thus leads to better shaped segmentation results. In the second part, we address another important issue, namely, alleviating the need for training segmentation models with large amounts of fully annotated data. We propose a novel attribution method that identifies the most significant regions in an image considered by classification networks. We then integrate our attribution method into a weakly supervised segmentation framework. The semantic segmentation models can thus be trained with only image-level labeled data, which can be easily collected in large quantities. All models proposed in this thesis are thoroughly experimentally evaluated on multiple datasets and the results are competitive with the literature
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El-Aff, Inhab Abdalla. "Visualisation of the electrical activities of the heart in 3D." Thesis, University of Salford, 2009. http://usir.salford.ac.uk/26652/.
Abstract:
The work described in this Thesis is concerned with developing a technique to visualise the electrical activities of the heart in 3D from ECG signals taken from sensors on the surface of the body. Generating such visualisations can help cardiologists to identify abnormal electrical propagation flows non-invasively. The approach taken has been to develop models for the body and the heart, followed by the implementation of the 'forward' solution, which calculates the body surface potential for excitations within the heart. The results obtained match published results. The 'inverse' solution, which determines the heart electrophysiology from the body surface measurements, was then implemented. Values derived from the 'forward' solution are then used to confirm the accuracy of the 'inverse' solution. The study has led to three improvements to existing approaches: a more realistic model of the heart's conduction system; and more effective solutions to both the 'forward' and 'inverse' calculations used to determine heart electro physiology. The methods that were developed were based on the biological and physiological properties of the heart tissues as well as the working methodology of the Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) scanner. Evaluation of the proposed techniques has been verified using seven methods, which include the location of Purkinje cells, the anatomy of the ventricle conduction system of the human heart, the Myocardium tissues to the Purkinje tissues ratio, the excitation propagation of the conduction system of the ventricles, the excitation isochrones of ventricles of the human heart, the generated body surface potential map and the generated 12 Lead ECG electrograms. A fundamentally new aspect of the work is to extract the conduction system of the ventricles from the DT-MRI providing a more realistic model for this structure, and this process has been accomplished by a semi-automatic manner, where extraction of the conduction system is accomplished with minimum manual processing and some simple image processing techniques. The Monodomain reaction diffusion equation, which is used to model the ventricle excitation propagation, has been updated to include the diffusion of the electrical stimulation in a non-uniform material, which is the more realistic case. The DT-MRI modality was employed for the first time to model the conduction system of the ventricles and to determine the relative non-uniform conductivity distribution inside the heart Myocardium. Unlike previous methods which consider an estimated conduction network for early activation points and assume the Myocardium material to be a uniform material, the new approach provide a more realistic solution for both the modelling of conduction system and the 'forward' solution. The 'inverse' solution is calculated for a localised multiple dipoles (sources) distribution inside the heart Myocardium based on transmembrance potential instead of current density, as currently used. This type of problem is highly illposed as the number of body surface readings is much fewer than the number of the heart dipoles (highly underdetermined). Employing the transmembrance potential reduces the size of the problem to a third of the current density solution and as a consequence it improves the localisation (due to the reduction of the underdeterminity) and reduces the memory usage and computational power to be 1/9 of the current density solution. Three equations have been derived to calculate the transfer matrix of the problem: the first one is for an isotropic source in a homogeneous-isotropic conductor; the second one is for an anisotropic source in a homogeneous-isotropic conductor; and the third one is for any type of source in an inhomogeneous-isotropic conductor. A low resolution version of the 'forward' model has been employed to simulate the 'forward' solution of the heart, and the body surface readings (200, 100, 64 and 32 electrodes) of that model were then used in the 'inverse' solution. Three regularisation techniques have been used to solve the Inverse Problem namely: the Minimum Norm (MN), the Weighted Minimum Norm (WMN) and the Exact Low Resolution Brain Electromagnetic Tomography technique (eLORETA). Results of these methods are compared to the original pacing points (1, 2, 3, 4, and 5 pacing points) which are used in the forward solution. It is concluded that the best results are obtained from the eLORETA method, and a large number of electrodes on the body surface and fewer number of sources leads to better results.
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Treece, Graham Michael. "Volume measurement and surface visualisation in sequential freehand 3D ultrasound." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621171.
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Castelli, Filippo Maria. "3D CNN methods in biomedical image segmentation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18796/.
Abstract:
A definite trend in Biomedical Imaging is the one towards the integration of increasingly complex interpretative layers to the pure data acquisition process. One of the most interesting and looked-forward goals in the field is the automatic segmentation of objects of interest in extensive acquisition data, target that would allow Biomedical Imaging to look beyond its use as a purely assistive tool to become a cornerstone in ambitious large-scale challenges like the extensive quantitative study of the Human Brain.
In 2019 Convolutional Neural Networks represent the state of the art in Biomedical Image segmentation and scientific interests from a variety of fields, spacing from automotive to natural resource exploration, converge to their development. While most of the applications of CNNs are focused on single-image segmentation, biomedical image data -being it MRI, CT-scans, Microscopy, etc- often benefits from three-dimensional volumetric expression.
This work explores a reformulation of the CNN segmentation problem that is native to the 3D nature of the data, with particular interest to the applications to Fluorescence Microscopy volumetric data produced at the European Laboratories for Nonlinear Spectroscopy in the context of two different large international human brain study projects: the Human Brain Project and the White House BRAIN Initiative.
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Jones, Jonathan-Lee. "2D and 3D segmentation of medical images." Thesis, Swansea University, 2015. https://cronfa.swan.ac.uk/Record/cronfa42504.
Abstract:
Cardiovascular disease is one of the leading causes of the morbidity and mortality in the western world today. Many different imaging modalities are in place today to diagnose and investigate cardiovascular diseases. Each of these, however, has strengths and weaknesses. There are different forms of noise and artifacts in each image modality that combine to make the field of medical image analysis both important and challenging. The aim of this thesis is develop a reliable method for segmentation of vessel structures in medical imaging, combining the expert knowledge of the user in such a way as to maintain efficiency whilst overcoming the inherent noise and artifacts present in the images. We present results from 2D segmentation techniques using different methodologies, before developing 3D techniques for segmenting vessel shape from a series of images. The main drive of the work involves the investigation of medical images obtained using catheter based techniques, namely Intra Vascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT). We will present a robust segmentation paradigm, combining both edge and region information to segment the media-adventitia, and lumenal borders in those modalities respectively. By using a semi-interactive method that utilizes "soft" constraints, allowing imprecise user input which provides a balance between using the user's expert knowledge and efficiency. In the later part of the work, we develop automatic methods for segmenting the walls of lymph vessels. These methods are employed on sequential images in order to obtain data to reconstruct the vessel walls in the region of the lymph valves. We investigated methods to segment the vessel walls both individually and simultaneously, and compared the results both quantitatively and qualitatively in order obtain the most appropriate for the 3D reconstruction of the vessel wall. Lastly, we adapt the semi-interactive method used on vessels earlier into 3D to help segment out the lymph valve. This involved the user interactive method to provide guidance to help segment the boundary of the lymph vessel, then we apply a minimal surface segmentation methodology to provide segmentation of the valve.
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Galisot, Gaëtan. "Segmentation incrémentale et interactive d'images médicales 3D." Thesis, Tours, 2018. http://www.theses.fr/2018TOUR4035.
Abstract:
Cette thèse présente une nouvelle méthode de segmentation interactive et incrémentale d'images médicales 3D. Nous proposons une manière plus locale, de modéliser les connaissances a priori décrivant les structures d'intérêt. Des relations spatiales sont également apprises entre ces régions et ont pour objectif de permettre le positionnement automatique des atlas locaux au sein de l'image entière. Lors de la segmentation, ces informations sont utilisées suivant un processus incrémental permettant de réaliser des segmentations partielles et rapides tout en choisissant l'ordre de segmentation des différentes régions. L'utilisateur peut intervenir sur le positionnement des atlas locaux afin d'améliorer la qualité de la segmentation obtenue. En outre, notre méthode englobe un post-traitement capable de corriger les erreurs systématiques que notre méthode de segmentation peut produireThis research work describes a new interactive and incremental method for the segmentation of 3D medical images. The a priori information associated to the anatomical structure to analyze is leamed in a local way. Several local atlases, each one describing only one anatomical structure are constwcted from a training dataset. Spatial relationships are also leamed between those regions aiming to position the local atlases inside the whole image. During the segmentation process, the graph is used in an incremental way allowing fast and partial segmentation. fle user can also interact during the local atlas posiboning in order toimprove the segmentation quality. A voxel classification by a hidden Markov random field is employed toprovide the local segmentations. We also propose s post-processing step in order to correct the systematiceuors that a segmentation can achieve
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McKinley, Joanne. "Volume Visualisation Via Variable-Detail Non-Photorealistic Illustration." Thesis, University of Waterloo, 2002. http://hdl.handle.net/10012/1104.
Abstract:
The rapid proliferation of 3D volume data, including MRI and CT scans, is prompting the search within computer graphics for more effective volume visualisation techniques. Partially because of the traditional association with medical subjects, concepts borrowed from the domain of scientific illustration show great promise for enriching volume visualisation. This thesis describes the first general system dedicated to creating user-directed, variable-detail, scientific illustrations directly from volume data. In particular, using volume segmentation for explicit abstraction in non-photorealistic volume renderings is a new concept. The unique challenges and opportunities of volume data require rethinking many non-photorealistic algorithms that traditionally operate on polygonal meshes. The resulting 2D images are qualitatively different from but complementary to those normally seen in computer graphics, and inspire an analysis of the various artistic implications of volume models for scientific illustration.
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Patera, Marianne. "The potential of 3D visualisation technology in art and design education." Thesis, Glasgow School of Art, 2009. http://radar.gsa.ac.uk/4735/.
Abstract:
This thesis investigates the potential of 3D visualisation technology for learning and teaching in Art and Design higher education. The aim of this research was not merely to employ the 3D technology but also to identify, design and evaluate an appropriate learning and teaching activity. Three empirical studies were conducted as part of this investigation on the topics of: Colour Theory Colour Experience Spatial Understanding The purpose of this study was to evaluate the effectiveness of the learning activity in its entirety, for learners, tutors and institutions. This research demonstrated that different educational topics may require different technological solutions. It proved that the implementation of carefully designed educational technology can enhance current learning, teaching and assessment processes in Art and Design education.
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Reynolds, Hayley Maria. "3D visualisation and analysis of skin lymphatic drainage patterns in melanoma." Thesis, University of Auckland, 2008. http://hdl.handle.net/2292/5792.
Abstract:
This thesis aimed to improve visualisation and analysis of potential patterns of melanoma spread from the skin to lymph nodes. For this purpose, anatomically based geometric models of the skin and lymph nodes have been created. A three-dimensional (3D) finite element (FE) skin model has been constructed using the Visible Human (VH) male dataset and a Sawbones head and neck model. A discrete lymph node model was also created using the VH dataset. This study has been conducted in collaboration with the SydneyMelanoma Unit (SMU), in Sydney, Australia. Clinicians at the SMU have recorded an extensive lymphoscintigraphy (LS) database, accurately mapping skin lymphatic drainage from over 5000 patients with cutaneous melanoma. The SMU’s entire LS database was mapped from two-dimensional LS images onto the 3D anatomical model. Melanoma sites were mapped onto the skin model using free-form deformation and projection techniques, while draining node fields were mapped onto a reduced lymph node model. Spatial heat maps were created using field fitting to visualise the likelihood that any area of skin would drain to a particular node field, or a specified number of node fields. An interactive skin selection tool was also developed to provide dynamic predictions of the draining node fields from any region of skin. The heat maps and interactive skin selection tool quantified that lymphatic drainage of the torso was highly complex, where the most unpredictable regions were located near Sappey’s lines. Drainage from skin on the upper and lower limbs was the most predictable, almost always draining to ipsilateral axillary and groin node fields respectively. Skin on the head and neck were shown to usually drain to two or more node fields, where the most common node fields were the cervical level II and preauricular node fields. Detailed statistical analysis was then conducted to investigate widely accepted assumptions about lymphatic drainage. Sappey’s lines were shown to be highly inaccurate at predicting lymphatic drainage from the skin of the torso. At least 12.5% of all melanoma sites located on the torso showed drainage across Sappey’s lines, and nearly the entire torso demonstrated ambiguous lymphatic drainage. A multinomial statistical model was fitted to the LS data to investigate whether lymphatic drainage was symmetric about the body’s vertical midline. Results showed that a significant proportion of the skin was likely to have symmetric lymphatic drainage patterns. Asymmetry that was shown within specific regions was likely due to an asymmetric distribution of melanoma sites within that region and/or a sparsity of data. Regions that indicated symmetry were reflected, providing a larger LS dataset to improve the statistical accuracy of drainage predictions. A cluster analysis was conducted using this reflected LS dataset to group regions of skin that drained in a similar manner. Results indicated that the dominant axillary, groin, cervical level II and preauricular node fields drained significant areas of skin. Clustering resulted in division of the torso into regions similar to Sappey’s lines, although an additional cluster formed in the middle of the anterior and posterior torso where predominantly ambiguous lymphatic drainage occurred. Confidence intervals were calculated using non-parametric bootstrapping to further determine the statistical accuracy of drainage predictions from each of these clusters. This body of research has been presented as four papers, which have either been published or will be submitted to international peer-reviewed journals: 1. Reynolds, H. M., Dunbar, P. R., Uren, R. F., Thompson, J. F. & Smith, N. P. (2007), ‘Mapping melanoma lymphoscintigraphy data onto a 3D anatomically based model’, Annals of Biomedical Engineering, 35:(8),1444-1457. 2. Reynolds, H. M., Dunbar, P. R., Uren, R. F., Blackett, S. A., Thompson, J. F. & Smith, N. P. (2007), ‘Three-dimensional visualisation of lymphatic drainage patterns in patients with cutaneous melanoma’, The Lancet Oncology, 8:(9),806-12. 3. Reynolds, H. M., Smith, N. P., Uren, R. F., Thompson, J. F., & Dunbar, P. R. (2008), ‘Threedimensional visualization of skin lymphatic drainage patterns from the head and neck’, Head & Neck, accepted. 4. Reynolds, H. M., Walker, C. G., Dunbar, P. R., O’Sullivan M. J., Uren, R. F., Thompson, J. F. & Smith, N. P. (2008), ‘Redefining the understanding of skin lymphatic drainage through statistical analysis’, submitted. This work has also been presented at the following three international conferences: 1. 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, New York, USA. Aug 30-Sep 3, 2006. 2. Biomedical Engineering Society 2007 Annual Fall Meeting, Los Angeles, California. Sep 26-29, 2007. 3. 6th International Sentinel Node Society Meeting. Sydney, Australia. Feb 18-20, 2008.Whole document restricted until September 2011, but available by request, use the feedback form to request access.
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Dobos, J. "Management and visualisation of non-linear history of polygonal 3D models." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1461400/.
Abstract:
The research presented in this thesis concerns the problems of maintenance and revision control of large-scale three dimensional (3D) models over the Internet. As the models grow in size and the authoring tools grow in complexity, standard approaches to collaborative asset development become impractical. The prevalent paradigm of sharing files on a file system poses serious risks with regards, but not limited to, ensuring consistency and concurrency of multi-user 3D editing. Although modifications might be tracked manually using naming conventions or automatically in a version control system (VCS), understanding the provenance of a large 3D dataset is hard due to revision metadata not being associated with the underlying scene structures. Some tools and protocols enable seamless synchronisation of file and directory changes in remote locations. However, the existing web-based technologies are not yet fully exploiting the modern design patters for access to and management of alternative shared resources online. Therefore, four distinct but highly interconnected conceptual tools are explored. The first is the organisation of 3D assets within recent document-oriented No Structured Query Language (NoSQL) databases. These "schemaless" databases, unlike their relational counterparts, do not represent data in rigid table structures. Instead, they rely on polymorphic documents composed of key-value pairs that are much better suited to the diverse nature of 3D assets. Hence, a domain-specific non-linear revision control system 3D Repo is built around a NoSQL database to enable asynchronous editing similar to traditional VCSs. The second concept is that of visual 3D differencing and merging. The accompanying 3D Diff tool supports interactive conflict resolution at the level of scene graph nodes that are de facto the delta changes stored in the repository. The third is the utilisation of HyperText Transfer Protocol (HTTP) for the purposes of 3D data management. The XML3DRepo daemon application exposes the contents of the repository and the version control logic in a Representational State Transfer (REST) style of architecture. At the same time, it manifests the effects of various 3D encoding strategies on the file sizes and download times in modern web browsers. The fourth and final concept is the reverse-engineering of an editing history. Even if the models are being version controlled, the extracted provenance is limited to additions, deletions and modifications. The 3D Timeline tool, therefore, implies a plausible history of common modelling operations such as duplications, transformations, etc. Given a collection of 3D models, it estimates a part-based correspondence and visualises it in a temporal flow. The prototype tools developed as part of the research were evaluated in pilot user studies that suggest they are usable by the end users and well suited to their respective tasks. Together, the results constitute a novel framework that demonstrates the feasibility of a domain-specific 3D version control.
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Berg, Madeleine Tamsin Lisa. "3D visualisation of melts at the conditions of Earth's deep interior." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20400.
Abstract:
Constraining the behaviour of small fractions of partial melt in a solid silicate matrix has been the focus of numerous experimental petrology studies over several decades, and is an important factor in constraining upper mantle rheology, melt extraction at mid-ocean ridges and mechanisms of core formation in the early solar system. Deformation of partially molten rock has been observed to change melt geometry, and may enhance permeability and interconnectivity of melt otherwise trapped in a solid silicate matrix, although it is uncertain how applicable results of high strain-rate laboratory experiments are to the real Earth. The addition of deformation precludes attainment of textural equilibrium, complicating textural analysis, which has previously relied on extrapolation of 3D textures from quenched and polished 2D sections for hydrostatically annealed samples. X-ray computed tomography gives the potential to visualise sample textures directly in three dimensions, and is becoming popular as a complementary technique for textural analysis in petrologic studies. The aim of this project has been to develop techniques to improve visualisation of small fractions of partial melt within a solid silicate matrix using X-ray CT, to examine textures of various partially molten systems at high PT in hydrostatic, and dynamically deforming systems. Experiments carried out in the FeS-melt, solid olivine system have examined the potential for deformation-enhanced percolation of core forming melts before the onset of silicate melting. Access to the newly designed rotational Paris-Edinburgh Cell (roPEC/rotoPEC) equipment has allowed us to carry out controlled, torsional deformation experiments under PT conditions applicable to planetary interiors. Experiments conducted at lower strain-rates over longer duration than in previously published studies show that deformation enhances connectivity at low melt fractions, at strain-rates down to 10-6s-1. This is in contrast to earlier work suggesting melt textures are unaffected at strain-rates below 10-5s-1. Quenched melt networks have been fully characterised in 3D using multi-scale CT, with voxel sizes down to 70nm for small sample sub-volumes. Results suggest segregation of metallic melt below the silicate solidus could be an efficient process, and should be taken into account in geochemical models of planetary evolution. Experiments on basaltic melt in a solid silicate matrix were conducted in application to upper mantle melting. A heavy element, hafnium, was added to the basaltic glass starting composition to enhance contrast between the basalt and olivine phases during CT scans. In-house micro-CT equipment was used to visualise post-quench run products of hydrostatic and deformation experiments. The doping technique was successful for long-duration, high temperature hydrostatic experiments. Some issues with undissolved / re-precipitated HfO¬2 crystals complicated tomographic imaging of partial melt textures in a number of experiments, particularly those carried out on the rotoPEC equipment, limiting comparison between samples. The doping technique requires further adjustment, but is shown to be a viable way to improve visibility of basaltic melt without significantly affecting melt texture. The X-ray transparent design and fully rotating top and bottom anvils of the rotoPEC allow X-ray tomography to be carried out in-situ while experiments are in progress, enabling collection of 4D datasets. During this project, the rotoPEC equipment was incorporated into two different synchrotron beamlines, to carry out time-resolved studies of textural development within samples of varying composition. The migration of gold melt along fractures with a BN matrix was imaged using 2D radiography, in combination with repeated 3D tomography to fully characterise the 3D fracture geometry. This allowed melt migration velocity to be estimated directly from in-situ observations. These techniques could be developed further to constrain melt migration processes quantitatively for a number of geological systems in the near future.
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Trellet, Mikael. "Exploration et analyse immersives de données moléculaires guidées par la tâche et la modélisation sémantique des contenus." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS262/document.
Abstract:
En biologie structurale, l’étude théorique de structures moléculaires comporte quatre activités principales organisées selon le processus séquentiel suivant : la collecte de données expérimentales/théoriques, la visualisation des structures 3d, la simulation moléculaire, l’analyse et l’interprétation des résultats. Cet enchaînement permet à l’expert d’élaborer de nouvelles hypothèses, de les vérifier de manière expérimentale et de produire de nouvelles données comme point de départ d’un nouveau processus.L’explosion de la quantité de données à manipuler au sein de cette boucle pose désormais deux problèmes. Premièrement, les ressources et le temps relatifs aux tâches de transfert et de conversion de données entre chacune de ces activités augmentent considérablement. Deuxièmement, la complexité des données moléculaires générées par les nouvelles méthodologies expérimentales accroît fortement la difficulté pour correctement percevoir, visualiser et analyser ces données.Les environnements immersifs sont souvent proposés pour aborder le problème de la quantité et de la complexité croissante des phénomènes modélisés, en particulier durant l’activité de visualisation. En effet, la Réalité Virtuelle offre entre autre une perception stéréoscopique de haute qualité utile à une meilleure compréhension de données moléculaires intrinsèquement tridimensionnelles. Elle permet également d’afficher une quantité d’information importante grâce aux grandes surfaces d’affichage, mais aussi de compléter la sensation d’immersion par d’autres canaux sensorimoteurs.Cependant, deux facteurs majeurs freinent l’usage de la Réalité Virtuelle dans le domaine de la biologie structurale. D’une part, même s’il existe une littérature fournie sur la navigation dans les scènes virtuelles réalistes et écologiques, celle-ci est très peu étudiée sur la navigation sur des données scientifiques abstraites. La compréhension de phénomènes 3d complexes est pourtant particulièrement conditionnée par la capacité du sujet à se repérer dans l’espace. Le premier objectif de ce travail de doctorat a donc été de proposer des paradigmes navigation 3d adaptés aux structures moléculaires complexes. D’autre part, le contexte interactif des environnements immersif favorise l’interaction directe avec les objets d’intérêt. Or les activités de collecte et d’analyse des résultats supposent un contexte de travail en "ligne de commande" ou basé sur des scripts spécifiques aux outils d’analyse. Il en résulte que l’usage de la Réalité Virtuelle se limite souvent à l’activité d’exploration et de visualisation des structures moléculaires. C’est pourquoi le second objectif de thèse est de rapprocher ces différentes activités, jusqu’alors réalisées dans des contextes interactifs et applicatifs indépendants, au sein d’un contexte interactif homogène et unique. Outre le fait de minimiser le temps passé dans la gestion des données entre les différents contextes de travail, il s’agit également de présenter de manière conjointe et simultanée les structures moléculaires et leurs analyses et de permettre leur manipulation par des interactions directes.Notre contribution répond à ces objectifs en s’appuyant sur une approche guidée à la fois par le contenu et la tâche. Des paradigmes de navigation ont été conçus en tenant compte du contenu moléculaire, en particulier des propriétés géométriques, et des tâches de l’expert, afin de faciliter le repérage spatial et de rendre plus performante l’activité d’exploration. Par ailleurs, formaliser la nature des données moléculaires, leurs analyses et leurs représentations visuelles, permettent notamment de proposer à la demande et interactivement des analyses adaptées à la nature des données et de créer des liens entre les composants moléculaires et les analyses associées. Ces fonctionnalités passent par la construction d’une représentation sémantique unifiée et performante rendant possible l’intégration de ces activités dans un contexte interactif uniqueIn structural biology, the theoretical study of molecular structures has four main activities organized in the following scenario: collection of experimental and theoretical data, visualization of 3D structures, molecular simulation, analysis and interpretation of results. This pipeline allows the expert to develop new hypotheses, to verify them experimentally and to produce new data as a starting point for a new scenario.The explosion in the amount of data to handle in this loop has two problems. Firstly, the resources and time dedicated to the tasks of transfer and conversion of data between each of these four activities increases significantly. Secondly, the complexity of molecular data generated by new experimental methodologies greatly increases the difficulty to properly collect, visualize and analyze the data.Immersive environments are often proposed to address the quantity and the increasing complexity of the modeled phenomena, especially during the viewing activity. Indeed, virtual reality offers a high quality stereoscopic perception, useful for a better understanding of inherently three-dimensional molecular data. It also displays a large amount of information thanks to the large display surfaces, but also to complete the immersive feeling with other sensorimotor channels (3D audio, haptic feedbacks,...).However, two major factors hindering the use of virtual reality in the field of structural biology. On one hand, although there are literature on navigation and environmental realistic virtual scenes, navigating abstract science is still very little studied. The understanding of complex 3D phenomena is however particularly conditioned by the subject’s ability to identify themselves in a complex 3D phenomenon. The first objective of this thesis work is then to propose 3D navigation paradigms adapted to the molecular structures of increasing complexity. On the other hand, the interactive context of immersive environments encourages direct interaction with the objects of interest. But the activities of: results collection, simulation and analysis, assume a working environment based on command-line inputs or through specific scripts associated to the tools. Usually, the use of virtual reality is therefore restricted to molecular structures exploration and visualization. The second thesis objective is then to bring all these activities, previously carried out in independent and interactive application contexts, within a homogeneous and unique interactive context. In addition to minimizing the time spent in data management between different work contexts, the aim is also to present, in a joint and simultaneous way, molecular structures and analyses, and allow their manipulation through direct interaction.Our contribution meets these objectives by building on an approach guided by both the content and the task. More precisely, navigation paradigms have been designed taking into account the molecular content, especially geometric properties, and tasks of the expert, to facilitate spatial referencing in molecular complexes and make the exploration of these structures more efficient. In addition, formalizing the nature of molecular data, their analysis and their visual representations, allows to interactively propose analyzes adapted to the nature of the data and create links between the molecular components and associated analyzes. These features go through the construction of a unified and powerful semantic representation making possible the integration of these activities in a unique interactive context
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Quartararo, John David. "Semi-automated segmentation of 3D medical ultrasound images." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-020509-161314/.
Abstract:
Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: 3d ultrasound; ultrasound; image processing; image segmentation; 3d image segmentation; medical imaging Includes bibliographical references (p.142-148).
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Paternesi, Claudio. "Virtual Reality Labelling Tool for 3D Semantic Segmentation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Abstract:
Durante gli ultimi anni nel campo della Computer Vision si sono susseguiti studi sempre più approfonditi sulla segmentazione semantica 3D, questi lavori richiedono spesso una enorme quantità di modelli 3D su cui fare le elaborazioni. Non sempre però, i dataset disponibili forniscono delle informazioni complete riguardanti anche la segmentazione dei modelli 3D. In questa tesi si propone uno strumento software con cui si possa creare, a partire da un modello 3D, la sua versione segmentata semanticamente, così da poter creare dei dataset completi da usare nelle fasi di training e test di modelli computazionali. Per garantire una buona usabilità e coinvolgere a pieno l’utente, il software è stato sviluppato tramite strumenti di realtà virtuale. Il tool è stato infine validato tramite dei test eseguiti su dei dataset già esistenti con l’obiettivo di valutare l’efficienza e l’accuratezza del software stesso.
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Engås, Asbjørn Breivik. "Segmentation of Right Ventricle in 3D Ultrasound Recordings." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8883.
Abstract:
This thesis presents segmentation of the right ventricle of the heart in real-time tracking of 3D ultrasound recordings. A simple deformable model for the right ventricle is developed based on statistical data from manual segmentations, and the model has been tested out in a set of 3D ultrasound recordings and compared to manually segmented right ventricular volumes. The manual segmentation method with volume approximation is also developed. The segmentation tests on the recordings are performed with an already present Kalman filter based real-time contour tracking framework. The ability of the models to fit to the shape of the right ventricle has been evaluated, and the resulting volume curves have been inspected. Deformable models of the right ventricle are constructed by placing nodes in an initial three-dimensional mesh, and subdivision schemes are applied to make smooth surfaces. There have also been experimented with models of different resolutions and initial positions. A background study of right ventricular anatomy, subdivision, model-based segmentation and Kalman filter theory is included, and clinical applications of volume measurements in real-time are suggested. The results of the segmentation are promising, and indicate that models adjust to the right ventricle during the heart beat.
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Ibrahim, Haidi. "Segmentation of the liver from 3D MRI data." Thesis, University of Surrey, 2005. http://epubs.surrey.ac.uk/842968/.
Abstract:
Three dimensional (3D) visualisation has the potential to significantly ease the decision making in presurgical planning. The first stage of creating a 3D model for this purpose is to segment the liver from magnetic resonance (MRI) images. However, MRI images often contain data corrupted by intensity variations in held strength due to the sensitivity of the radio frequency (rf) coils used in the A/IRI scanner. In this thesis, we investigate several approaches to arrive at a solution to overcome this inhomogeneity problem, and at the same time, improve the image quality. These experiments show that the use of local enhancement, followed by median filtering, and toboggan contrast enhancement, is a good solution to achieve this aim. We then automate a segmentation technique known as intelligent scissors to segment the liver. The user only needs to select an initial slice, and the method is executed automatically. From the initial slice, the contour propagates inside the volume and segments the liver in every slice using a dynamic programming algorithm.
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Quartararo, John David. "Semi-Automated Segmentation of 3D Medical Ultrasound Images." Digital WPI, 2009. https://digitalcommons.wpi.edu/etd-theses/155.
Abstract:
A level set-based segmentation procedure has been implemented to identify target object boundaries from 3D medical ultrasound images. Several test images (simulated, scanned phantoms, clinical) were subjected to various preprocessing methods and segmented. Two metrics of segmentation accuracy were used to compare the segmentation results to ground truth models and determine which preprocessing methods resulted in the best segmentations. It was found that by using an anisotropic diffusion filtering method to reduce speckle type noise with a 3D active contour segmentation routine using the level set method resulted in semi-automated segmentation on par with medical doctors hand-outlining the same images.