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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.
1

Plant canopy modeling from Terrestrial LiDAR System distance and intensity data / Modélisation géométrique de la canopée des plantes à partir des données d'intensité et de distance fournies par un Système LiDAR Terrestre

Balduzzi, Mathilde 24 November 2014 (has links)
Le défi de cette thèse est de reconstruire la géométrie 3D de la végétation à partir des données de distance et d'intensité fournies par un scanner de type LiDAR. Une méthode de « shape-from-shading » par propagation est développée pour être combinée avec une méthode de fusion de données type filtre de Kalman pour la reconstruction optimale des surfaces foliaires.-Introduction-L'analyse des données LiDAR nous permet de dire que la qualité du nuage de point est variable en fonction de la configuration de la mesure : lorsque le LiDAR mesure le bord d'une surface ou une surface fortement inclinée, il intègre dans sa mesure une partie de l'arrière plan. Ces configurations de mesures produisent des points aberrants. On retrouve souvent ce type de configuration pour la mesure de feuillages puisque ces derniers ont des géométries fragmentées et variables. Les scans sont en général de mauvaise qualité et la quantité d'objets présents dans le scan rend la suppression manuelle des points aberrants fastidieuse. L'objectif de cette thèse est de développer une méthodologie permettant d'intégrer les données d'intensité LiDAR aux distances pour corriger automatiquement ces points aberrants. -Shape-From-Shading-Le principe du Shape-From-Shading (SFS) est de retrouver les valeurs de distance à partir des intensités d'un objet pris en photo. La caméra (capteur LiDAR) et la source de lumière (laser LiDAR) ont la même direction et sont placés à l'infini relativement à la surface, ce qui rend l'effet de la distance sur l'intensité négligeable et l'hypothèse d'une caméra orthographique valide. En outre, la relation entre angle d'incidence lumière/surface et intensité est connue. Par la nature des données LiDAR, nous pourrons choisir la meilleure donnée entre distance et intensité à utiliser pour la reconstruction des surfaces foliaires. Nous mettons en place un algorithme de SFS par propagation le long des régions iso-intenses pour pouvoir intégrer la correction de la distance grâce à l'intensité via un filtre de type Kalman. -Design mathématique de la méthode-Les morceaux de surface correspondant aux régions iso-intenses sont des morceaux de surfaces dites d'égales pentes, ou de tas de sable. Nous allons utiliser ce type de surface pour reconstruire la géométrie 3D correspondant aux images d'intensité.Nous démontrons qu'à partir de la connaissance de la 3D d'un bord d'une région iso-intense, nous pouvons retrouver des surfaces paramétriques correspondant à la région iso-intense qui correspondent aux surfaces de tas de sable. L'initialisation de la région iso-intense initiale (graine de propagation) se fait grâce aux données de distance LiDAR. Les lignes de plus grandes pentes de ces surfaces sont générées. Par propagation de ces lignes (et donc génération du morceau de la surface en tas de sable), nous déterminons l'autre bord de la région iso-intense. Puis, par itération, nous propagerons la reconstruction de la surface. -Filtre de Kalman-Nous pouvons considérer cette propagation des lignes de plus grande pente comme étant le calcul d'une trajectoire sur la surface à reconstruire. Dans le cadre de notre étude, la donnée de distance est toujours disponible (données du scanner 3D). Ainsi il est possible de choisir, lors de la propagation, quelle donnée (distance ou intensité) utiliser pour la reconstruction. Ceci peut être fait notamment grâce à une fusion de type Kalman. -Algorithme-Pour procéder à la reconstruction par propagation, il est nécessaire d'hiérarchiser les domaines iso-intenses de l'image. Une fois que les graines de propagation sont repérées, elles sont initialisées avec l'image des distances. Enfin, pour chacun des nœuds de la hiérarchie (représentant un domaine iso-intense), la reconstruction d'un tas de sable est faite. C'est lors de cette dernière étape qu'une fusion de type Kalman peut être introduite. / The challenge of this thesis is reconstruct the 3D geometry of vegetation from distance and intensity data provided by a 3D scanner LiDAR. A method of “Shape-From-Shading” by propagation is developed to be combined with a fusion method of type “Kalman” to get an optimal reconstruction of the leaves. -Introduction-The LiDAR data analysis shows that the point cloud quality is variable. This quality depends upon the measurement set up. When the LiDAR laser beam reaches the edge of a surface (or a steeply inclined surface), it also integrate background measurement. Those set up produce outliers. This kind of set up is common for foliage measurement as foliages have in general fragmented and complex shape. LiDAR data are of bad quality and the quantity of leaves in a scan makes the correction of outliers fastidious. This thesis goal is to develop a methodology to allow us to integrate the LiDAR intensity data to the distance to make an automatic correction of those outliers. -Shape-from-shading-The Shape-from-shading principle is to reconstruct the distance values from intensities of a photographed object. The camera (LiDAR sensor) and the light source (LiDAR laser) have the same direction and are placed at infinity relatively to the surface. This makes the distance effect on intensity negligible and the hypothesis of an orthographic camera valid. In addition, the relationship between the incident angle light beam and intensity is known. Thanks to the LiDAR data analysis, we are able to choose the best data between distance and intensity in the scope of leaves reconstruction. An algorithm of propagation SFS along iso-intense regions is developed. This type of algorithm allows us to integrate a fusion method of type Kalman. -Mathematical design of the method-The patches of the surface corresponding to the iso-intense regions are patches of surfaces called the constant slope surfaces, or sand-pile surfaces. We are going to use those surfaces to rebuild the 3D geometry corresponding to the scanned surfaces. We show that from the knowledge of the 3d of an iso-intensity region, we can construct those sand-pile surfaces. The initialization of the first iso-intense regions contour (propagation seeds) is done with the 3D LiDAR data. The greatest slope lines of those surfaces are generated. Thanks to the propagation of those lines (and thus of the corresponding sand-pile surface), we build the other contour of the iso-intense region. Then, we propagate the reconstruction iteratively. -Kalman filter-We can consider this propagation as being the computation of a trajectory on the reconstructed surface. In our study framework, the distance data is always available (3D scanner data). It is thus possible to choose which data (intensity vs distance) is the best to reconstruct the object surface. This can be done with a fusion of type Kalman filter. -Algorithm-To proceed a reconstruction by propagation, it is necessary to order the iso-intensity regions. Once the propagation seeds are found, they are initialized with the distances provided by the LiDAR. For each nodes of the hierarchy (corresponding to an iso-intensity region), the sand-pile surface reconstruction is done. -Manuscript-The thesis manuscript gathers five chapters. First, we give a short description of the LiDAR technology and an overview of the traditional 3D surface reconstruction from point cloud. Then we make a state-of-art of the shape-from –shading methods. LiDAR intensity is studied in a third chapter to define the strategy of distance effect correction and to set up the incidence angle vs intensity relationship. A fourth chapter gives the principal results of this thesis. It gathers the theoretical approach of the SFS algorithm developed in this thesis. We will provide its description and results when applied to synthetic images. Finally, a last chapter introduces results of leaves reconstruction.
2

MeatSpace

Criscuolo, Nicholas M 29 October 2019 (has links)
“MeatSpace” is a group of related bodies of work including podcasts, prints and videos produced by working with simulation technologies such as “weak A.I.”, virtual reality, and 3d scans. Collectively the works explore how people relate to these technologies and how they relate to us. They share thematic or process-oriented sensibilities involving a series of rule-based steps that alternate between the procedural and the intentional. “Uncanny” is defined as strangely familiar. Something which falls in the Uncanny Valley feels wrong, but the reasons may be difficult to articulate. “MeatSpace” is an ongoing experiment to see where our own digital reflections fall in an uncanny spectrum of unsettling familiarity. I am continuously assessing the meaning of words like “consciousness" and “choice”, wondering if they are simply interpretations of randomness and determinism. So I search for genuine glimmers of agency in technologies from the present and the past to better understand my own. The groupings within “MeatSpace” are titled “The Intrinsia Chatbox” (podcast), “Outside the Chatbox” (podcast), “Sweet Space/Spatial Awareness”(prints, video, augmented reality), “Formulaics”(music videos), and “Texture Maps/Morph Maps” (prints, video). “MeatSpace” uses manipulation of photogrammetry, volumetric video capture, procedural music generation, animations made in virtual reality, and a video podcast which showcases conversations with chatbots. I see these as acts of collaboration and play with the digital world and it’s developing tools and inhabitants. These processes employ both randomness and control, operating between meatspace and the digital world, between comfort and the uncanny valley.
3

Jednoválcový motor pro silniční motocykl / Single-cylinder Engine of a Road Motorcycle

Čech, Martin January 2016 (has links)
This thesis is focusing on the construction of a four-stroke internal combustion engine for a 250 ccm road bike. Since it is a road bike, the introduction of legislation of the Czech Republic for this category is outlined in the introduction of the thesis. Furthermore, disassembling of similar and competitive engine was conducted. The thesis also describes the process of construction of this four-stroke internal combustion engine. In addition, the thesis compares friction loss on the main bearing crankshaft. In the latter part there is summarization of all findings.
4

Náhrada části lidských kostí umělými materiály s využitím 3D tisku / Replacement of human bones by synthetic materials using 3D printing

Svoboda, Štěpán January 2017 (has links)
The thesis is divided into three main parts. The first section summarizes the theory of the issue. Here we are unified theoretical information about the various possibilities of different approaches. The result of this part is therefore a general summary of theoretical possible procedures of creation bone implant, where each are listed the advantages and disadvantages. The theoretical part also contains information that ultimately, in practice, the author did not use. But his idea was to create a comprehensive look at the issue from several angles. The second part uses theoretical knowledge from the previous set of information as a basis for defining the steps required to successfully manage the issues of bone 3D printing. The third part will follow the guidelines of both previous and focuses on practical making bones and subsequent evaluation method chosen. There are discussed various steps that led to the final conclusion, making bones and work is then focused on the evaluation of the success of selected procedures and recommendations for future action.
5

CNC obrábění součásti hřídel převodovky / CNC machining of shaft from gearbox

Konvičný, Denis January 2020 (has links)
The diploma thesis deals with the production of gearbox shaft components using a CNC machine tool, shaft programming in Tebis 4.0 R8 software, Sinumerik SinuTrain 7.5, and manufacturing accuracy checking using 3D scanning technology, which allows you to compare the CAD model and the scan of the manufactured part.
6

VYUŽITÍ 3D TECHNOLOGIÍ VE VEŘEJNÉM PROSTORU / THE USE OF 3D TECHNOLOGY IN THE PUBLIC SPACE

Šebánek, Jan Unknown Date (has links)
The aim of this thesis is to define the impact of rapid prototyping technology in terms of creative potential to use this technology represents a particularly sculpture and architecture. Rapid Prototyping is a generic term covering a range of technologies: 3D scan converting the already realistic three-dimensional objects in computer memory, parametric modeling, which creates three-dimensional objects based on the formative algorithms, photogrammetry method of compiling three-dimensional object from a photo, technology, 3D printing materializing after each layer objects transferred from the computer's memory. When processing the theoretical work will be explored and discussed possibilities for realization of basic three-dimensional objects using 3D technology. The second step will be to map the different methods of access to artists working with 3D technology. In the end it tried to evaluate the benefits of these technologies in the field of sculpture and architecture in terms of traditional approaches. This paper attempts to describe the possible implications and potential of this progressive field in the classical artistic disciplines such as sculpture and architecture, both in terms of benefits and in terms of the eventual negative impact with respect to increasing the availability of this technology.
7

Aufbereitung von 3D-Scandaten zur additiven Fertigung von orthopädischen Helmschalen mit Fusion 360 und Geomagic FreeForm

Matthes, Jörg, Petzold, Claudius, Mauersberger, Valentin 05 July 2019 (has links)
Im Rahmen des Forschungsprojektes ,,Entwicklung eines 3D Hochgeschwindigkeits-Rotationsdruckverfahren' an der Hochschule Mittweida, wird sich mit dem Erzeugen eines CAD-Modells eines Patientenschädels und der passgenauen Modellierung einer orthopädischen Helmschale für diesen beschäftigt. Ziel ist es die zeitintensive Modellherstellung mittels Gips einzusparen und die endgültige Helmschale im .stl-Format zu erzeugen. Weiter wird, mittels einer visuellen Programmierumgebung, ein Programm erzeugt um die Helmschale in einem polaren Koordinatensystem für den geplanten Hochgeschwindigkeits-Rotations-3D-Drucker auszurichten, zu slicen und die Koordinaten der einzelnen Punkte der Bahnkurven der Extruder auszugeben.
8

Study of the possibilities of 3D-printing for Footwear design and development of models for this new market. : Studie av möjligheterna med 3D-printing för Skodesign och utveckling av modeller för denna nya marknad.

Jimenez Moreno, Enrique January 2022 (has links)
The fashion industry is going through a radical change with new technologies. Footwear designers are taking advantage of CAD-software to create groundbreaking models. However, it is not only from a design point of view that the field is changing, 3D-printing technology is becoming an alternative for manufacturing footwear against the contaminating mass-producing system adopted by the fashion industry, challenging the traditional trading system of the products. Starting with a market analysis and user’s research and incorporating later CAD modeling, 3D-scanning and 3D-printing, the following project develops a design workflow for 3D-printing footwear and presents the readers with fresh designs to compete in the market.

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