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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.
21

3D skener pro výukové účely / 3D scanner for educational purposes

Romanovský, Jiří January 2017 (has links)
This diploma thesis deals with the design of a 3D optical scanner using the structured light projection method. The aim of this thesis is to demonstrate the principles and processes of 3D scanning by using the DLP LightCrafter projector and the ImagingSource camera. The individual stages of the measurement process will be implemented to the Matlab software environment to describe the various principles and methods which can be used for digitizing the objects.
22

Korekce barev 3D scanneru a 3D tiskárny / Color Correction for 3D scanner and 3D printer

Kratochvíla, Michael January 2019 (has links)
This thesis deals with color correction of a chain that starts with the 3D Artec MHT scanner, and ends with the 3D printers (CJP – Color Jet Printing technology). In principle, it is necessary to control the color interpretation of the entire chain from the scanning of real models to the 3D print model. With color properties and their color shade, including color textures. The principle of model surface scanning using a 3D scanner is in the same principle as photo camera which scans using a conventional CMOS chip. For this reason, color palettes were scanned using the photo camera and the resulting digital data were analyzed by the Darktable software. This analysis consisted of comparing the scanned color shades of the surface with the spectrofotometer measured data. The main goal of this method was to achieve color precision in the digital data during their acquirement, adjustment and interpretation. Then the same principle was applied to the data acquired by the 3D scanner to create an ICC profile of the 3D scanner. Because the 3D printer (CJP – Color Jet Printing) uses the same principle as the 2D printer, the 2D printing device calibration principle was used again to calibrate it. There have been defined procedures that adjust the color shade to the spectrophotometrically correct shades of the resulting print on a 3D printer. Color swatches were also printed for print quality verification. It has been found that with photo camera, which was used for objective measurement in the L*a*b* coordinates of independent space, any color setting and their adjustment is very sensitive to even small imprecisions. It has been found that it is not easy to obtain accurate colors within the Detla E
23

Automatizovaný systém pro skenování konstrukčních dílů / Automated System for Components Scanning

Hřib, Jan January 2021 (has links)
The aim of this thesis is to design an automated scanning system for components for the purpose of inspecting their dimensions and tolerances. The theoretical introduction provides the reader with basic information on the topic of 3D scanning. The work also includes the design of own scanning system. The greatest attention is paid to the design of a program using the PCL library. The aim of the program is automatic processing of data from a 3D scanner and evaluation of the required dimensions of the scanned component. The final part of the work is devoted to testing the proposed solution.
24

Frekvenčně modální analýza lopatkového svazku parní turbíny / Frequency modal analysis of blade package of steam turbine

Přikryl, František January 2009 (has links)
This thesis deals with comparison the results of the frequency modal analysis of blade package of steam turbine with stiffening or damping bounding elements. Computational model was created through the finite element method, using cyclical symmetry. The results were compared with experimental analysis and analysis in VIPACK programme. Thesis also contains creating the solid blade model, using the reverse engineering.
25

Návrh bezsynchronní převodovky závodního automobilu / Non-synchronous Gearbox Design for Racing Cars

Pokorný, Lukáš January 2011 (has links)
The thesis focuses on the design of an appropriate reconstruction of automobile gearboxes for racing cars. It describes the steps necessary to create the final solution. It also describes the work of the ATOS 3D scanner and software Engineer.
26

Devaluing the <em>mitqal</em> : Inherent Trading Fees in the Metrics of Birka

Schultzén, Joakim January 2009 (has links)
<p>Abstract: Previous research on the Viking Age trade centre of Birka has suggested the parallel use of two harmonising standard weight units, differing in mass by five percent. As an explanation to this phenomenon, this paper puts forward a hypothesis of a trading fee, embedded in the weights. This is corroborated through a hypothetical deductive study; including a reassertion of earlier results by means of a new method for archaeometrological analysis, using a 3D scanner and Computer-Aided Design. Further, the role of silver, as a preferred unit of payment in Birka, is supported through a spatial analysis of the distribution of Islamic coins and Oriental beads in the provinces of Middle Sweden. Plausible manufacturing sites for the cylindrical lead weights, adhering to the Birka mitqal, are discussed as a possible way of falsifying the hypothesis. The results suggest that a trading fee was extracted, using the Birka mitqal for imports and the Islamic mitqal for exports. The metrological analysis was also expanded to weights from Sigtuna, which proved the Birka mitqal, as well the dual metrics system, continued to be in use there until, at least, the first half of the 11<sup>th</sup> century. Finally, a short study on the origins of the Scandinavian/Islamic weight system suggests that the direct influence for the system primarily can be attributed the Volga-Bulgarians.</p>
27

Devaluing the mitqal : Inherent Trading Fees in the Metrics of Birka

Schultzén, Joakim January 2009 (has links)
Abstract: Previous research on the Viking Age trade centre of Birka has suggested the parallel use of two harmonising standard weight units, differing in mass by five percent. As an explanation to this phenomenon, this paper puts forward a hypothesis of a trading fee, embedded in the weights. This is corroborated through a hypothetical deductive study; including a reassertion of earlier results by means of a new method for archaeometrological analysis, using a 3D scanner and Computer-Aided Design. Further, the role of silver, as a preferred unit of payment in Birka, is supported through a spatial analysis of the distribution of Islamic coins and Oriental beads in the provinces of Middle Sweden. Plausible manufacturing sites for the cylindrical lead weights, adhering to the Birka mitqal, are discussed as a possible way of falsifying the hypothesis. The results suggest that a trading fee was extracted, using the Birka mitqal for imports and the Islamic mitqal for exports. The metrological analysis was also expanded to weights from Sigtuna, which proved the Birka mitqal, as well the dual metrics system, continued to be in use there until, at least, the first half of the 11th century. Finally, a short study on the origins of the Scandinavian/Islamic weight system suggests that the direct influence for the system primarily can be attributed the Volga-Bulgarians.
28

Computer vision techniques for early detection of skin cancer

Quintana Plana, Josep 14 June 2012 (has links)
This thesis investigates the problem of developing new computer vision techniques for early detection of skin cancer. The first part of this work presents a novel methodology to correct color reproduction in dermatological images when different cameras and/or dermoscopes are used. Next, the problem of automatic full body mapping is addressed by proposing a mosaicing method based on an on-the-shelf digital compact camera and a set of markers. This method increases the possibilities of total body photography by taking the low-resolution images of a whole body exploration and automatically combining them into a high-resolution photomosaic. The third contribution of this work consists of the development of a full body scanner for acquiring cutaneous images. On one hand, the scanner reduces the long time-consuming examinations done in dermoscopy explorations, and on the other hand, it increases the resolution of total body photography systems. / En aquesta tesi s'investiga el desenvolupament de noves tècniques de visió per computador per a la detecció del càncer de pell. La primera part del treball presenta una nova metodologia per a la correcció del color en imatges dermatològiques quan s'utilitzen diferents càmeres i/o els dermatoscops. A continuació és proposa una solució al problema del registre automàtic d'imatges de cos complert amb la proposta d’un mètode de mosaicing basat en l'ús de càmeres compactes i un conjunt de markers. Incrementant les possibilitats de la fotografia de cos complert mitjançant la combinació automàtica d’imatges de baixa resuloció per a l'obtenció d'un fotomosaic d’alta resolució. La tercera contribució d'aquest treball consisteix en el desenvolupament d'un escàner de cos complert per a l'adquisició d'imatges cutànies. D'una banda l'escàner redueix el llarg temps necessari per a les exploracions dermatoscòpiques, i de l'altre, incrementa la resolució de la fotografia de cos complet.
29

Exterior inspection of an aircraft using a Pan-Tilt-Zoom camera and a 3D scanner moved by a mobile robot : 2D image processing and 3D point cloud analysis / Inspection de l'extérieur d'un aéronef à partir d'une caméra Pan-Tilt-Zoom et d'un scanner 3D portés par un robot mobile : analyse d'images et de nuages de points 3D

Jovančević, Igor 21 November 2016 (has links)
Cette thèse s’inscrit dans le cadre d’un projet industriel multi-partenaires ayant pour objectif le développement d’un robot mobile collaboratif (un cobot), autonome dans ses mouvements au sol, capable de réaliser l’inspection visuelle d’un aéronef, à la fois en phase de petite ou grande maintenance dans un hangar ou en phase de pré-vol sur le tarmac d’un aéroport. Le cobot est équipé de capteurs lui permettant d’effectuer ses tâches de navigation autonome, mais également d’un ensemble de capteurs optiques constituant la tête d’inspection : une caméra orientable Pan-Tilt-Zoom et un scanner 3D qui délivrent respectivement des données sous forme d’images 2D et de nuages de points 3D. L’objectif de la thèse est de développer des algorithmes d’analyse d’images 2D et de nuages de points 3D, afin d’établir un diagnostic sur l’état de l’avion et son aptitude à voler. Nous avons développé des algorithmes pour vérifier certains éléments de l’appareil, tels que valves, portes, capteurs, pneus ou moteurs, et également pour détecter et caractériser des dommages 3D sur le fuselage (impacts, rayures, etc.). Nous avons exploité dans nos algorithmes les connaissances a priori disponibles, en particulier le modèle 3D CAO de l’avion (un AIRBUS A320 dans le cadre de nos essais). Durant ces travaux de la thèse, nous avons pu répondre à deux besoins (parfois antagonistes) : développer des algorithmes d’inspection rapides et robustes, mais également répondre aux exigences spécifiques d’un projet industriel qui visait à développer un prototype opérationnel. Nous nous sommes attachés à développer des algorithmes les plus génériques possibles, de manière à ce qu’ils puissent être utilisés pour d’autres types d’inspection, tels que l’inspection de bâtiments ou de navires par exemple. Nous avons aussi contribué au développement du prototype (robot mobile équipé de capteurs) en développant le module de contrôle des capteurs d’inspection et en intégrant nos codes sur le robot avec les autres modules développés par les partenaires. Le prototype a fait l’objet de nombreux essais en hangar de maintenance ou sur tarmac. / This thesis makes part of an industry oriented multi-partners project aimed at developing a mobile collaborative robot (a cobot), autonomous in its movements on the ground, capable of performing visual inspection of an aircraft during short or long maintenance procedures in the hangar or in the pre-flight phase on the tarmac. The cobot is equipped with sensors for realizing its navigation tasks as well as with a set of optical sensors which constitute the inspection head: an orientable Pan-Tilt-Zoom visible light camera and a three-dimensional scanner, delivering data in the format of two-dimensional images and three-dimensional point clouds, respectively. The goal of the thesis is to propose original approaches for processing 2D images and 3D clouds, with intention to make a decision with respect to the flight readiness of the airplane. We developed algorithms for verification of the aircraft items such as vents, doors, sensors, tires or engine as well as for detection and characterization of three-dimensional damages on the fuselage. We integrated a-priori knowledge on the airplane structure, notably numerical three-dimensional CAD model of the Airbus-A320. We argue that with investing effort to develop robust enough algorithms and with the help of existing optical sensors to acquire suitable data, we can come up with non-invasive, accurate, and time-efficient system for automatic airplane exterior inspection. The thesis work was placed in between two main requirements: develop inspection algorithms which could be as general as possible and also meet the specific requirements of an industry oriented project. Often, these two goals do not go along and the balance had to be made. On one side, we were aiming to design and assess the approaches that can be employed on other large structures, for ex. buildings, ships. On the other hand, writing source code for controlling sensors as well as integrating our whole developed source code with other modules on the real-time robotic system, were necessary in order to demonstrate the feasibility of our robotic prototype.
30

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."

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