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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Projeto e construção de um scanner antropométrico baseado no método de triangulação a laser.

Gazziro, Mario Alexandre 30 August 2005 (has links)
Made available in DSpace on 2016-06-02T19:06:26Z (GMT). No. of bitstreams: 1 DissMAG.pdf: 11643347 bytes, checksum: dcaf64ea49dba6f68c7f414fd7f548a0 (MD5) Previous issue date: 2005-08-30 / Three-dimensional (3D) surface anthropometry enables us to extend the study to 3D geometry and morphology of human body. The purpose of this study is to build a whole 3D body scanner. Using lasers and cameras mounted on a scanning platform moved by a single motor and controlled by an embedded controller, a device has been implemented to capture the shape of the entire human body. One application case study (body fat percentage) is presented. The results suggests that the developed scanner can be useful for that particular case study and other like size surveying and medicine. / Um scanner antropométrico possibilita ampliar nossos estudos sobre geometria e morfologia tridimensional do corpo humano. O propósito desse estudo é construir um scanner 3D para todo o corpo humano. Utilizando lasers e câmeras instalados em uma plataforma movida por um único motor, controlado por um dispositivo dedicado, foi implementado um equipamento que permite a aquisição das formas do corpo inteiro. Uma aplicação para estudo de caso (determinação do percentual de gordura) é apresentada. Os resultados sugerem que o scanner desenvolvido pode ser útil para este caso de estudo em particular, além de outras aplicações tais como em censos antropométricos e em medicina.
302

Estudo sobre a aplicabilidade do processo de inventário funcional de pavimentos rígidos com o emprego do equipamento Pavement Scanner e validação de resultados. / Research on the applicability of the functional inventory of rigid pavements with the use of Pavement Scanner equipment and results validation.

Daniel Torres Scabello 20 April 2018 (has links)
O gerenciamento de uma malha rodoviária engloba avaliações constantes das condições estruturais e, principalmente, funcionais. Assim sendo, uma forma de coleta automatizada, realizada em velocidades de tráfego, em que a influência humana possa ser desconsiderada, está em desenvolvimento na engenharia rodoviária brasileira, assim como é visto internacionalmente. O presente trabalho tem como objetivo a contribuição para o processo de avaliação funcional de pavimentos através do estudo sobre a aplicabilidade do processo de inventário funcional de pavimentos rígidos com o emprego do equipamento Pavement Scanner. Para tanto, após a revisão bibliográfica sobre a sistemática de inventário de pavimentos rígidos e também sobre o equipamento Pavement Scanner, seções testes foram definidas e avaliadas de acordo com o método tradicional de levantamento da superfície do pavimento (ICP - DNIT 062/PRO, DNIT 060/PRO), o método volumétrico tradicional de mancha de areia para avaliação de macrotextura (ASTM E 965/96), através de imageamento com análise de imagens obtidas no trecho e sob a utilização do equipamento Pavement Scanner. Com os resultados foi realizada uma análise estatística destas técnicas utilizadas, demonstrando a viabilidade de utilização do equipamento e do procedimento de análise adotado. / The management of a road network encompasses constant assessments of structural conditions and, above all, functional conditions. Thus, a form of automated survey, carried out at traffic speeds, in which human influence can be unconsidered, is under development in Brazilian road engineering, as it is seen internationally. This present work aims to contribute to the process of functional assessment of pavements through the study of applicability of the functional inventory process of rigid pavements with the use of Pavement Scanner equipment. In order to do so, after the literature review of rigid pavement inventory and Pavement Scanner equipment, test sections were defined and evaluated according to the traditional method of surface survey (ICP - DNIT 062 / PRO, DNIT 060 / PRO), the traditional sand patch volumetric method for the evaluation of macrotexture (ASTM E 965/96), through imaging analysis from the test sections and under the use of Pavement Scanner equipment. With the results, a statistical analysis of these techniques were performed, demonstrating the feasibility of using the equipment and the analysis procedure adopted.
303

Caractéristiques physiques et chimiques fines des cendres volcaniques : application à la téphrostratigraphie / Fine physical and chemical features of volcanic ashes : applications to tephrostratigraphy

Jouannic, Gwenolé 17 June 2015 (has links)
Le but de ce travail a été de réaliser des études téphrostratigraphiques sur des environnements sédimentaires variés dans le but de définir, dans un premier temps, le degré d'efficacité des techniques de détection des téphras classiquement utilisées. Le travail d'analyse des cendres volcaniques a tout d'abord été ciblé sur des téphras clés et anciennement étudiés sur des sites reconnus, en Belgique et dans le Massif du Jura, dans le but d'actualiser des données avec les techniques d'analyses performantes actuelles. Le travail a ensuite été étendu à des sites de l'Est du Massif Central, dont le potentiel téphrostratigraphique n'avait jamais été exploité, offrant ainsi la possibilité de s'assurer sans ambiguïté de la source de cryptotéphras repérés dans le Jura et en Suisse, dont l'origine était incertaine. Ce travail d'échantillonnage a été réalisé dans des milieux lœssiques, carbonatés et tourbeux permettant également de discuter des conditions de conservation des dépôts volcaniques et de leurs constituants. Les études téphro-chrono-stratigraphiques s'inscrivent fréquemment dans une réflexion sur l'impact écologique et environnemental des éruptions volcaniques. Un nombre croissant d'études tendent à montrer un impact écologique des téphras, en étant la cause de bloom de diatomées. Ce travail de thèse a permis de discuter de cet aspect environnemental qui a été mené dans le Jura, dans un environnement défavorable à la préservation des diatomées. / The challenge of this work was to carry out several tephrostratigraphic studies in various sedimentary environments in order to test the efficiency of classical detection methods of tephra layers. First, analysis has been focused on tephra keys, previously studied in known sites, in Belgium and in the Jura Mountains, in order to update data with current analytical techniques. This work was later expanded to sites from eastern French Massif Central, an area with unexploited tephrostratigraphic potential, which offers the possibility to precise the source of cryptotephras identified in the Jura and Switzerland whose origin was uncertain. This work has been carried out in tephras sampled in loess, carbonate maris and peat allowing to discuss conservation conditions of volcanic deposits. Sorne tephro-chrono-stratigraphic studies show ecological and environmental impacts of volcanic deposits in lakes and peatlands, such as diatom blooms. This thesis allows to discuss this environmental aspect in carbonate maris, i.e. an unfavorable environment for preservation of diatoms.
304

Développement d'un endomicroscope multiphotonique compact et flexible pour l'imagerie in vivo haute résolution de tissus biologiques non marqués / Development of a compact and flexible multiphoton endomicroscope for in vivo high-resolution imaging of label-free biological tissues

Ducourthial, Guillaume 24 September 2014 (has links)
La microscopie multiphotonique est un outil essentiel d’investigation en biologie cellulaire et tissulaire. Son extension à l’endoscopie est l’objet d’intenses efforts de recherche pour des applications en neurosciences (imagerie cérébrale du petit animal) ou en clinique (diagnostic précoce, aide à la biopsie). Ce manuscrit porte sur le développement d’un endomicroscope multiphotonique présentant des performances inédites. Ce dispositif est alimenté par un oscillateur titane-saphir standard. Vient ensuite un module de pré-compensation des distorsions linéaires et non linéaires se produisant dans la fibre endoscopique. Ce module permet d’obtenir des impulsions compressées de 39 fs à la sortie d’une fibre microstructurée air-silice innovante à double gaine de 5 mètres de long qui est optimisée pour l’excitation multiphotonique (cœur central de 3,4 µm à maintien de polarisation) et la collection du signal produit par les cibles biologiques. A l’extrémité de la fibre, on trouve une sonde endoscopique, de 2,2 mm de diamètre pour 37 mm de long, composée d’un micro-scanner à fibre optique et d’un micro-objectif achromatique de distance de travail supérieure à 400 µm. La résolution spatiale de l’appareil vaut 0,83 µm et l’acquisition se fait en simultané sur deux canaux spectraux à 8 images/s. L’appareil a permis l’enregistrement d’images in vivo sans marquage des tubules et de la capsule rénale, respectivement par fluorescence à deux photons des flavines et par génération de second harmonique du collagène, avec 30 mW sur les tissus et jusqu’à 300 µm sous la surface de l’organe. / Multiphoton microscopy is an essential investigative tool in cell and tissue biology. Its extension to endoscopy is the subject of intensive research for applications in neuroscience (brain imaging of small animals) or clinical (early diagnosis, help for biopsy). This manuscript focuses on the development of an endomicroscope with multiphoton unprecedented performance. This device is powered by a standard titanium-sapphire oscillator. Then comes a pre-compensation module of linear and nonlinear distortions occurring in the endoscopic fiber. This module provides compressed pulses of 39 fs at the direct output of 5 meters long innovative double-clad air-silica microstructured fiber which is optimized for multiphoton excitation (polarization maintaining central core of 3.4 µm) and the collection of the signal produced by biological targets. At the end of the fiber, there is an endoscopic probe, 2.2 mm in diameter and 37 mm long, composed of a micro fiber scanning system and an achromatic micro-objective with a working distance greater than 400 µm. The spatial resolution of the device is 0.83 µm and the acquisition is done simultaneously on two spectral channels at 8 frames/s. The device has recorded in vivo images without label of the tubules and the renal capsule, respectively by two-photon excitation fluorescence of flavins and second harmonic generation of collagen, with 30 mW on the tissues and 300 µm below the surface of the organ.
305

Consolidation de relevés laser d'intérieurs construits : pour une approche probabiliste initialisée par géolocalisation / Registration of indoor TLS data : in favor of a probabilistic approach initialized by geolocation

Hullo, Jean-Francois 10 January 2013 (has links)
La préparation d'interventions de maintenance dans les installations industrielles a dorénavant recours à des outils d'étude, de modélisation et de simulation basés sur l'exploitation de modèles virtuels 3D des installations. L'acquisition de ces modèles tridimensionnels s'effectue à partir de nuages de points mesurés, depuis plusieurs points de vue, par balayage angulaire horizontal et vertical d'un faisceau laser par scanner laser terrestre. L'expression dans un repère commun de l'ensemble des données acquises est appelée consolidation, au cours de laquelle les paramètres de changement de repères entre les stations sont calculés. L'objectif de cette thèse est d'améliorer la méthode d'acquisition de données laser en environnements industriels. Celle-ci doit, au final, garantir la précision et l'exactitude nécessaires des données tout en optimisant le temps et les protocoles d'acquisition sur site, en libérant l'opérateur d'un certain nombre de contraintes inhérentes au relevé topographique classique. Nous examinons, dans un premier temps, l'état de l'art des moyens et méthodes mis en œuvre lors de l'acquisition de nuages de points denses de scènes d'intérieurs complexes (Partie I). Dans un deuxième temps, nous étudions et évaluons les données utilisables pour la consolidation: données laser terrestres, algorithmes de reconstruction de primitives et systèmes de géolocalisation d'intérieur (Partie II). Dans une troisième partie, nous formalisons et expérimentons ensuite un algorithme de recalage basé sur l'utilisation de primitives appariées, reconstruites dans les nuages de points (Partie~III). Nous proposons finalement une approche probabiliste de l'appariement de primitives permettant l'intégration des informations et incertitudes a priori dans le système de contraintes utilisé pour le calcul des poses (Partie IV). / Many pre-maintenance operations of industrial facilities currently resort on to three-dimensional CAD models. The acquisition of these models is performed from point clouds measured by Terrestrial Laser Scanning (TLS). When the scenes are complex, several viewpoints for scanning, also known as stations, are necessary to ensure the completeness and the density of the survey data. The generation of a global point cloud, i.e. the expression of all the acquired data in a common reference frame, is a crucial step called registration. During this process, the pose parameters are estimated. If the GNSS systems are now a solution for many outdoor scenes, the registration of indoor TLS data still remains a challenge. The objective of this thesis is to improve the acquisition process of TLS data in industrial environments. The aim is to guarantee the precision and accuracy of acquired data, while optimizing on-site acquisition time and protocols by, as often as possible, freeing the operator from the constraints inherent to conventional topographic surveys. In a first part, we consider the state of the art of the means and methods used during the acquisition of dense point clouds of complex interior scenes (Part I). In a second part, we study and evaluate the data available for the registration: terrestrial laser scanner data, primitive reconstruction algorithms in point clouds and indoor geolocation systems (Part II). In the third part, we then formalize and experiment a registration algorithm based on the use of matched primitives, reconstructed from per station point clouds (Part III). We finally propose a probabilistic approach for matching primitives, allowing the integration of a priori information and uncertainty in the constraints system used for calculating poses (Part IV).
306

Measuring dimensions of goods modules with 2D laser scanners on a conveyor belt / Dimensionsmätning av godsmoduler på ett transportband med 2D-laserskannrar

Strandberg, Filip, Freij, Johan January 2017 (has links)
A company wants to measure and verify the size of goods modules, transported on a conveyor belt, with the help of two 2D laser scanners (LMS100). The resulting measurements will be written to a database whereafter the modules will be moved by an automatic lifting device to a storage. The dimensions and possible any protrusions need to be known to avoid collision. The goal with this project is to write three modular libraries. One library for communicating with the LMS100 scanner, one library for calculating the dimensions of the goods modules and one library for handling the database. A graphical user interface (GUI) was also created which was implemented with an existing graphical library, Simple Directmedia Layer (SDL). A Raspberry Pi 3 has been used as a hardware platform which communicates with two LMS100 via ethernet. All code is written in the programming language C. LMS100 communicates with so called telegrams and the library implements these with TCP sockets. The structure of these can be found in the manufacturer’s datasheet. The calculating library uses trigonometric functions with measurement values from the scanners. The database library uses sqlite3 for a serverless database. The testing of these libraries was first done on a small scale with only one scanner and a small box placed a few decimeters in front of the scanner, to verify the functionality of the libraries. The company later provided a larger test rig with a remote controlled  platform, which drove between the scanners. When measuring objects with this test rig, the system showed an adequate ability to verify the size of the goods module. An inherent measurement error of a few millimeters of the scanners is shown, but this doesn’t affect the functionality in the final product which will measure considerably larger objects. Some functions are prepared for future development but aren’t yet ready for use. The protrusions of the goods modules aren’t yet discovered by the system. The calculating library is prepared to be able to detect these, but the evaluation of them aren’t ready. If the goods module is at an angle, the system measurements will be faulty. For every scanned segment the coordinates are saved and in future development it will be able to detect the angle. / Ett företag vill med hjälp av två stycken 2D-laserskannrar (LMS100) mäta och verifiera storleken på godsmoduler som transporteras på ett transportband. Mätresultatet ska skrivas till en databas varefter modulerna med en automatiskt styrd avlastare förflyttar dem till ett lager. Dimensioner och eventuella utstick på modulen måste vara kända för att undvika kollision. Målet med arbetet är att skriva tre stycken modulära bibliotek. Ett bibliotek för kommunikation med LMS100, ett bibliotek för beräkning av godsmodulens dimensioner och ett bibliotek för databashantering. Till detta skapades även ett grafiskt användargränssnitt (GUI) som implementerades med hjälp av ett färdigt grafikbibliotek, Simple Directmedia Layer (SDL).  En Raspberry Pi 3 har använts som hårdvaruplattform som kommunicerar med två stycken LMS100 via ethernetanslutning. All kod skrivs i programspråket C. LMS100 kommunicerar med s.k. telegram och biblioteket implementerar dessa via TCP sockets. Strukturen på dessa går att läsa i tillverkarens datablad. Beräkningsbiblioteket använder trigonometriska funktioner med mätvärden från skannrarna för beräkning. Databasbiblioteket använder sig av sqlite3 för en serverlös databas. Testning av dessa bibliotek skedde först på en småskalig nivå med endast en skanner och en liten låda placerad några decimeter framför skannern,  för att verifiera funktionaliteten på berörda bibliotek. Företaget bidrog senare med en testrig i större skala med en fjärrstyrd plattform, som körde mellan de två skannrarna. Vid mätning av objekt i denna testrig visade systemet en tillräckligt god förmåga för att kunna verifiera storlek på godsmoduler. Ett medföljt mätfel i millimeterskala finns i skannrarna, men detta påverkar inte funktionaliteten i den slutgiltiga produkten som ska mäta mycket större objekt. Vissa funktioner är förberedda för framtida utveckling men är inte färdiga för användning. Utstick på godsmodulerna upptäcks inte av systemet än. Beräkningsbiblioteket är förberett för att kunna upptäcka dessa, men utvärderingen av dem är inte färdigt. Om godsmodulen är vriden på transportbandet mäter systemet fel. Koordinater finns för varje skannat segment så att man ska kunna upptäcka denna vinkel i framtida utveckling.
307

Mikrospiegel basierte 3D Scannersysteme für Reverse Engineering Lösungen in einem weiten Skalenbereich

Aswendt, Petra 26 September 2017 (has links) (PDF)
Aus der Einleitung: "In der Historie erforderte die komplette dreidimensionale Aufnahme eines Objektes mittels Streifenprojektion einen hohen Zeitaufwand aufgrund der Realisierung der zeitlichen Abfolge von Streifensequenzen mit analogen Mitteln, mehrere Sekunden sind der übliche Standard für eine 3D Aufnahme. Damit einher geht die Notwendigkeit des während der Aufnahmezeit ruhenden Objektes. Das bedeutet Einschränkungen für eine Vielzahl von Anwendungen insbesondere bei dynamischen Prozessen und lebenden Objekten. Neue Möglichkeiten eröffneten sich mit der Einführung digitaler Lichtmodulatoren."
308

Coxiella burnetii : de la culture aux manifestations cliniques / Coxiella burnetii : from culture to clinical manifestations

Eldin, Carole 07 February 2017 (has links)
C. burnetii est une bactérie intracellulaire strcite. Récemment, un milieu axénique, nommé ACCM 2 a été développé, et permet la culture de cette bactérie en atmosphère microaérophile. Nous avons testé si l’ajout d’acide urique dans le milieu de culture pouvait permettre une culture en milieu aérobie. Nous avons observé une croissance de C. burnetii incubée en conditions aérobies dans le milieu ACCM2 enrichi en acide urique. A Cayenne, en Guyane Française, les pneumopathies causées par C. burnetii sont fréquentes et sévères. Nous avons analysé le génome d’une souche isolée à Cayenne. Ce travail a mis en évidence une délétion de 6105 pb intéressant le gène du système de sécrétion de type 1 (T1SS). Cette réduction de génome est probablement impliquée dans l’hypervirulence des souches de Cayenne. Enfin, nous avons testé la sensibilité aux antibiotiques de 6 souches isolées à partir de patients vivant à Cayenne. Ces souches étaient toutes sensibles à la doxycycline et résistantes aux macrolides. Dans une troisième partie nous avons analysé l’apport du TEP scanner dans le diagnostic des infections à C. burnetii. 167 patients atteints d’infections à C. burnetii ont bénéficié d’un TEP scanner. Nous avons retrouvé une proportion élevée de fixations ostéo-articulaires (21) et ganglionnaires (27), et nous avons proposé de nouvelles définitions pour ces localisations. Nous avons ensuite étudié l’impact du traitement chirurgical chez les patients atteints d’infections vasculaires. Une analyse rétrospective de 86 patients atteints d’infections vasculaires a montré que la chirurgie était associée à une diminution de la mortalité à 2,5 ans et à une meilleure évolution sérologique / C. burnetii is an intracellular bacterium. Recently, an axenic medium, named ACCM 2, has been developed and allows the culture of this bacterium in a microaerophilic atmosphere. We tested if the addition of uric acid in the medium could allow an aerobic culture. We observed growth of C. burnetii incubated under aerobic conditions in the ACCM2 medium enriched with uric acid. In Cayenne, French Guiana, pneumonia caused by C. burnetii are frequent and severe. We analyzed the genome of a strain from Cayenne. This work revealed a 6105 bp deletion in the gene of the type 1 secretion system (T1SS). This genome reduction is probably involved in the hypervirulence of Cayenne strains. Finally, we tested the antibiotic suceptibility of 6 strains isolated from patients living in Cayenne. These strains were all susceptible to doxycycline and resistant to macrolides. In a third part we analyzed the contribution of PET scanner in the diagnosis of C. burnetii infections. 167 patients with C. burnetii infections benefited from a PET scan. We found a high proportion of osteo-articular (21) and lymphadenitis (27) fixations, and we proposed new definitions for these locations. We then investigated the impact of surgical treatment in patients with vascular infections. A retrospective analysis of 86 patients with vascular infections showed that surgery was associated with a lower mortality at 2.5 years and a better serological outcome
309

Geometric And Radiometric Estimation In A Structured-Light 3D Scanner

Dhillon, Daljit Singh J S 05 1900 (has links) (PDF)
Measuring 3D surface geometry with precision and accuracy is an important part of many engineering and scientific tasks. 3D Scanning techniques measure surface geometry by estimating the locations of sampled surface points. In recent years, Structured-Light 3D scanners have gained significant popularity owing to their ability to produce highly accurate scans in real-time at a low cost. In this thesis we describe an approach for Structured-Light 3D scanning using a digital camera and a digital projector. We utilise the projective geometric relationships between the projector and the camera to carry out both an implicit calibration of the system and to solve for 3D structure. Our approach to geometric calibration is flexible, reliable and amenable to robust estimation. In addition, we model and account for the radiometric non-linearities in the projector such as gamma distortion. Finally, we apply a post-processing step to efficiently smooth out high-frequency surface noise while retaining the structural details. Consequently, the proposed work reduces the computational load and set-up time of a Structured-Light 3D scanner; thereby speeding up the whole scanning process while retaining the ability to generate highly accurate results. We demonstrate the accuracy of our scanning results on real-world objects of varying degrees of surface complexity. Introduction The projective geometry for a pair of pin-hole viewing devices is completely defined by their intrinsic calibration and their relative motion or extrinsic calibration in the form of matrices. For a Euclidean reconstruction, the geometry elements represented by the calibration matrices must be parameterised and estimated in some form. The use of a projector as the ‘second viewing’ device has led to numerous approaches to model and estimate its intrinsic parameters and relative motion with respect to the camera's 3D co-ordinate system. Proposed thesis work assimilates the benefits of projective geometry constructs such as Homography and the invariance of the cross-ratios to simplify the system calibration and the 3D estimation processes by an implicit modeling of the projector's intrinsic parameters and its relative motion. Though linear modeling of the projective geometry between a camera-projector view-pair captures the most essential aspects of the underlying geometry, it does not accommodate system non-linearities due to radiometric distortions of a projector device. We propose an approach that uses parametric splines to model the systematic errors introduced by radiometric non-linearities and thus correct for them. For 3D surfaces reconstructed as point-clouds, noise manifests itself as some high-frequency variations for the resulting mesh. Various pre and/or post processing techniques are proposed in the literature to model and minimize the effects of noise. We use simple bilateral filtering of the depth-map for the reconstructed surface to smoothen the surface while retaining its structural details. Modeling Projective Relations In our approach for calibrating the projective-geometric structure of a projector-camera view-pair, the frame of reference for measurements is attached to the camera. The camera is calibrated using a commonly used method. To calibrate the scanner system, one common approach is to project sinusoidal patterns onto the reference planes to generate reference phase maps. By relating the phase-information between the projector and image pixels, a dense mapping is obtained. However, this is an over-parameterisation of the calibration information. Since the reference object is a plane, we can use the projective relationships induced by a plane to implicitly calibrate the projector geometry. For the estimation of the three-dimensional structure of the imaged object, we utilise the invariance of cross-ratios along with the calibration information of two reference planes. Our formulation is also extensible to utilise more than two reference plane to compute more than one estimate of the location of an unknown surface point. Such estimates are amenable to statistical analysis which allows us to derive both the shape of an object and associate reliability scores to each estimated point location. Radiometric Correction Structured-light based 3D scanners commonly employ phase-shifted sinusoidal patterns to solve for the correspondence problem. For scanners using projective geometry between a camera and a projector, the projector's radiometric non-linearities introduce systematic errors in establishing correspondences. Such errors manifest as visual artifacts which become pronounced when fewer phase-shifted sinusoidal patterns are used. While these artifacts can be avoided by using a large number of phase-shifts, doing so also increases the acquisition time. We propose to model and rectify such systematic errors using parametric representations. Consequently, while some existing methods retain the complete reference phase maps to account for such distortions, our approach describes the deviations using a few model parameters. The proposed approach can be used to reduce the number of phase-shifted sinusoidal patterns required for codification while suppressing systematic artifacts. Additionally, our method avoids the 1D search steps that are needed when a complete reference phase map is used, thus reducing the computational load for 3D estimation. The effectiveness of our method is demonstrated with reconstruction of some geometric surfaces and a cultural figurine. Filtering Noise For a structured-light 3D scanner, various sources of noise in the environment and the devices lead to inaccuracies in estimating the codewords (phase map) for an unknown surface, during reconstruction. We examine the effects of such noise factors on our proposed methods for geometric and radiometric estimation. We present a quantitative evaluation for our proposed method by scanning the objects of known geometric properties or measures and then computing the deviations from the expected results. In addition, we evaluate the errors introduced due to inaccuracies in system calibration by computing the variance statistics from multiple estimates for the reconstructed 3D points, where each estimate is computed using a different pair of reference planes. Finally, we discuss the efficacy of certain filtering techniques in reducing the high-frequency surface noise when applied to: (a) the images of the unknown surface at a pre-processing stage, or (b) the respective phase (or depth) map at a post-processing stage. Conclusion In this thesis, we motivate the need for a procedurally simple and computationally less demanding approach for projector calibration. We present a method that uses homographies induced by a pair of reference planes to calibrate a structured-light scanner. By using the projective invariance of the cross-ratio, we solved for the 3D geometry of a scanned surface. We demonstrate the fact that 3D geometric information can be derived using our approach with accuracy on the order of 0.1 mm. Proposed method reduces the image acquisition time for calibration and the computational needs for 3D estimation. We demonstrate an approach to effectively model radiometric distortions for the projector using cubic splines. Our approach is shown to give significant improvement over the use of complete reference phase maps and its performance is comparable to that of a sate-of-the-art method, both quantitatively as well as qualitatively. In contrast with that method, proposed method is computationally less expensive, procedurally simpler and exhibits consistent performance even at relatively higher levels of noise in phase estimation. Finally, we use a simple bilateral filtering on the depth-map for the region-of-interest. Bilateral filtering provides the best trade-off between surface smoothing and the preservation of its structural details. Our filtering approach avoids computationally expensive surface normal estimation algorithms completely while improving surface fidelity.
310

Modélisation dynamique et suivi de tumeur dans le volume rénal / Dynamic modeling and tumor tracking for the kidney

Leonardi, Valentin 13 November 2014 (has links)
Ce travail de thèse porte sur la modélisation dynamique 3D du rein et le suivi d’une tumeur de cet organe. Il s’inscrit dans le projet KiTT (Kidney Tumor Tracking) qui regroupe des chercheurs issus de plusieurs domaines : la modélisation géométrique, la radiologie et l’urologie. Le cadre de cette thèse suit une tendance de mini-invasivité des gestes chirurgicaux observée ces dernières années (HIFU, coelioscopie). Sa finalité est d’aboutir à un nouveau protocole de destruction de tumeurs rénales totalement non-invasif, par la diffusion d’agents physiques (ondes d’ultrasons) à travers la peau et focalisés sur la tumeur. Devant le mouvement et la déformation que le rein présente au cours du cycle respiratoire, la problématique de ces travaux de recherche est de connaître en permanence la position de la tumeur afin d’ajuster à moyen terme la diffusion des ondes en conséquence. / This Ph.D. thesis deals with the 3D dynamic modeling of the kidney and tracking a tumor of this organ. It is in line with the KiTT project (Kidney Tumor Tracking) which gathers researchers from different fileds: geometric modeling, radiology and urology. This work arised from the tendency of nowadays surgical gestures to be less and less invasive (HIFU, coelioscopy). Its goal is to result in a totally non-invasive protocol of kidney tumors eradication by transmitting ultrasound waves through the skin without breaking in it. As the kidney presents motions and deformations during the breathing phase, the main issue is to know the kidney and tumor positions at any time in order to adjust the waves accordingly.

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