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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

Atomization-based Spray Coating for Improved 3D Scanning

Valinasab, Behzad 27 May 2014 (has links)
Obtaining geometrical and physical information of industrially manufactured products or manually created artifacts has increased dramatically in the past few years. These data are usually generated by means of specific devices which are called 3D scanners. 3D scanners generate virtual 3D models of objects which in different fields can be used for various applications such as reverse engineering and quality control in manufacturing industry or data archiving of valuable unique objects of cultural heritage. There are basically two types of 3D scanning depending on whether contact or non-contact techniques are used. Non-contact scanners have been developed to overcome the problems of contacts. Optical methods are the most developed and major category of non-contact scanning techniques. Remarkable progress in computer science has been the key element of optical 3D scanning development. Apart from this improvement, optical scanners are affected by surface characteristics of the target object, such as transparency and reflectivity, since optical scanners work based on reflected light from the object surface. For solving this problem, in most cases the object is sprayed with an aerosol spray to change its characteristics temporarily, e.g. from shiny to dull or transparent to opaque. It is important to apply coating of minimum possible thickness to keep the object geometry unchanged. To study this issue, an atomization-based spray coating system was developed in this thesis research and used in sets of experiments to evaluate the effects of thin layer coating on 3D scanning results. In this thesis, firstly the spray coating system structure and coating specifications will be offered. Then, for appraising the efficiency of atomization-based spray coating in 3D scanning process, some examples are presented. These examples are based on some actual parts from different industries which were used as target objects to be coated and scanned. / Graduate / 0548 / behzadv@uvic.ca
2

Atomization-based Spray Coating for Improved 3D Scanning

Valinasab, Behzad 27 May 2014 (has links)
Obtaining geometrical and physical information of industrially manufactured products or manually created artifacts has increased dramatically in the past few years. These data are usually generated by means of specific devices which are called 3D scanners. 3D scanners generate virtual 3D models of objects which in different fields can be used for various applications such as reverse engineering and quality control in manufacturing industry or data archiving of valuable unique objects of cultural heritage. There are basically two types of 3D scanning depending on whether contact or non-contact techniques are used. Non-contact scanners have been developed to overcome the problems of contacts. Optical methods are the most developed and major category of non-contact scanning techniques. Remarkable progress in computer science has been the key element of optical 3D scanning development. Apart from this improvement, optical scanners are affected by surface characteristics of the target object, such as transparency and reflectivity, since optical scanners work based on reflected light from the object surface. For solving this problem, in most cases the object is sprayed with an aerosol spray to change its characteristics temporarily, e.g. from shiny to dull or transparent to opaque. It is important to apply coating of minimum possible thickness to keep the object geometry unchanged. To study this issue, an atomization-based spray coating system was developed in this thesis research and used in sets of experiments to evaluate the effects of thin layer coating on 3D scanning results. In this thesis, firstly the spray coating system structure and coating specifications will be offered. Then, for appraising the efficiency of atomization-based spray coating in 3D scanning process, some examples are presented. These examples are based on some actual parts from different industries which were used as target objects to be coated and scanned. / Graduate / 0548 / behzadv@uvic.ca
3

Wie der Computer virtuelle Muskeln formt

Neumann, Thomas, Wacker, Markus 27 May 2014 (has links) (PDF)
Mit Techniken der Computergraphik können bewegte drei-dimensionale Oberflächen mit höchsten visuellen Details generiert und dargestellt werden. Mittlerweile sind die Ergebnisse so gut, dass beispielsweise virtuelle menschliche Gesichter in Filmen und Videospielen kaum noch von realen zu unterscheiden sind. Auch in der Ergonomie werden immer genauere Mensch-Modelle und Simulationen verwendet, beispielsweise zur Validierung und Verbesserung von Textilien.
4

Tracing Ice age artistic communities: 3D modeling finger flutings in the Franco-Cantabrian

Huang, Hsin-yee Cindy 09 January 2019 (has links)
Finger flutings are lines and markings drawn with the human hand in soft cave sediment in caves and rock shelters throughout southern Australia, New Guinea and southwestern Europe, dating back to the Late Pleistocene. Analysis of these markings can reveal characteristics of the creators, such as age, sex and group sizes. However, despite a comprehensive method of study, data collection is still reliant on in field measurements and is often constrained by physical challenges within the caves. Advances in technology allow us to record archaeological data in three dimensions. Creating 3D models of finger fluting panels would allow for off-site measurements and other forms of detailed analysis. In this thesis, I test three different 3D scanning techniques, photogrammetry, tripod structured light scanning, and handheld structured light scanning, to determine the most appropriate method for the documentation of finger flutings based on factors such as portability, cost, efficiency, accuracy, as well as other challenges present in cave and rock shelter settings. I created replica fluting panels in three different media and created 3D models of them. I then compared measurements taken from the panels in person to measurements taken from the 3D-scanned models to see if there is statistically significant difference between the models and the panel. The results of my experiment show that 3D models of finger fluting panels are accurate representations of the experimental panels and that photogrammetry is the technique that best meets the requirements of finger fluting research. / Graduate
5

Extraoral 3D-scanning - conformity between extraoral 3D scanning and clinical measurements of the face

Persson, Angelica, Lindewald, Amanda January 2021 (has links)
Aim: To use the extraoral scanner 3D Sense in practice and compare the measurements on scanned material with conventional, direct clinical measurements. This is to evaluate if extraoral scanning can replace a clinical examination and extraoral 2D photography. Material & method: Fifteen adults at the Faculty of Odontology were recruited for the study. Five determined landmarks were marked in the faces of the subjects. Direct clinical measurements were performed between the landmarks of every subject and used as a reference. The subjects' faces were scanned and the same distances were measured in the scans. Differences in measurements of the two methods were conducted in a paired t-test. Intra- and inter operator differences were calculated for all distances. Intraclass correlations were used to describe to what extent subjects in the same group resemble each other.  Results: Conformity of direct clinical measurements and measurements on scanned material varied between the mean difference of 0,22-5,13 mm. Intra- and inter operator ICC was overall excellent. Conclusion: The measurements between the landmarks pronasale (prn) and pogonion (pg) was the only distance with no statistical significant difference between the two methods. The 3D Sense shows decreasing conformity to clinical measurements with increasing distances. Inter operator ICC shows excellent values and measuring on scanned material can be regarded as a reproducible method. The results indicate clinical acceptance for use of 3D Sense for some purposes in odontology. 3D Sense has been validated in-vitro and analyzed in-vivo. The studies have established the 3D Sense’s adequacy in odontology.
6

Plumage

Sewell, Gwendolyn Vera 21 April 2017 (has links)
Plumage is a stereoscopic 3D experience showcasing the culmination of a personal exploration and observation of birds: a digitally modeled and rendered, fantastical bird referred to simply as a Phoenix. In many cultures birds are tied to ideas of freedom, power, and the otherworldly. Preconceived notions of a phoenix exist across many cultures as well, but for this project I wanted to create my own interpretation. While working, I drew upon my admiration of birds for their qualities of strength, beauty, and curiosity to infuse into the project. Inspired by the dynamic and detailed works of naturalists like John James Audubon, I took the opportunity to make my own observations and records of birds. I began exploring different processes of digitizing three-dimensional forms by scanning bird skins. However, due to the nature of fibrous and reflective materials (of which birds are often both) I ran into challenges that made accurate and detailed representation difficult if not impossible. From there I made the decision to pursue a more imaginative artistic approach to the project. More than just a homage to feathers and birds, this project represents the continued value of artists in the field of preservation and their ability to push visuals further with their own observations where automation and digitization fall short. Using life references I created my own textures and forms with details meant to emulate my favorite aspects of the birds that inspired me throughout my journey. Larger-than-life, projected stereoscopic 3D allows the audience to see details clearly and enhances the dynamic quality of the piece; both very important elements that needed to shine through in the final artwork. Plumage is made possible through the use of the Cyclorama, a series of convex screens that surround an audience and allow them to appreciate scenes projected in stereoscopic 3D. / Master of Fine Arts
7

Multispektrální 3D skenování s vysokým rozlišením a jeho aplikace v medicíně / High-Resolution Multispectral 3D Scanning and its Medical Applications

Chromý, Adam January 2017 (has links)
Termovizní zobrazování i 3D skenování jsou v současné době rychle se rozvíjející technologie. Obě technologie mají mnoho výhod, které by mohly být užitečné v medicíně. Jejich datová fúze přináší ještě více nových diagnostických informací, než kdyby byly použity samostatně. Cílem této práce je vývoj multispektrálního 3D skenovacího systému založeného na novém způsobu snímání pomocí robotického manipulátoru vybaveného laserovým snímačem, teplotní kamerou a barevnou kamerou. Navržené řešení přináší jak flexibilitu, tak přesnost. Tento systém skenování je dále využit v klinických aplikacích, aby byly ověřeny jeho schopnosti a ukázány přínosy nad rámec současného stavu techniky.
8

Design paramétrico a partir da digitalização 3D de geometrias da natureza com padrão de crescimento espiral

Silva, Luciano Santos da January 2017 (has links)
A modelagem de geometrias da natureza pode ser um processo complexo devido ás características orgânicas dos elementos. Propõe-se com essa dissertação identificar geometrias espaciais que sigam o padrão de crescimento espiral observado na natureza, utilizando as Tecnologias 3D como ferramentas para o processo de projeto. Para a execução do trabalho foram investigadas os Métodos de Biônica, Crescimento Espiral e a Sequência de Fibonacci, Engenharia Reversa e Design Paramétrico. O processo de representação dos elementos foi realizado em conformidade com a Metodologia para o Desenvolvimento de Produtos Baseados no Estudo da Biônica com o acréscimo das tecnologias de digitalização tridimensional e de processamento de nuvem de pontos, complementado pela parametrização de superfícies à base de curvas. Foram utilizados três processos para modelagem de curvas paramétricas representadas (i) pelo desenho de linhas sobre a malha digitalizada em 3D, (ii) por programação visual no software Grasshopper e (iii) por programação com scripts Python. Foi avaliada como melhor alternativa para o Design Paramétrico a utilização da programação visual otimizada com a programação por scripts, a qual apresentou melhor aproximação entre as curvas analisadas. Estudos de casos realizados com elementos da natureza (abacaxi e pinha) demonstraram a viabilização do método. Desta maneira a sistematização do conhecimento permitirá a proposição de um modelo paramétrico baseado na Biônica para fase inicial de inspiração e concepção de alternativas do projeto de produto. / Modeling the geometries of nature can be a complex process due to the organic characteristics of the elements. It is proposed with this dissertation to identify spatial geometries that follow the pattern of spiral growth observed in nature, using 3D Technologies as tools for the design process. For the execution of the work were investigated the Bionics, Spiral Growth and Fibonacci Sequence, Reverse Engineering and Parametric Design. The process of representation of the elements was carried out in accordance with the Methodology for the Development of Products Based on the Study of the Bionics with the addition of the technologies of three-dimensional digitization and processing of cloud of points, complemented by the parameterization of surfaces based on curves. Three methods were used for modeling parametric curves represented by (i) the drawing of lines on the 3D scanned mesh, (ii) by visual programming in the Grasshopper software and (iii) by programming with Python scripts. It was evaluated as the best alternative for Parametric Design the use of optimized visual programming with programming by scripts, which presented better approximation between the analyzed curves. Case studies carried out with nature elements (pineapple and pine cone) demonstrated the viability of the method. In this way the systematization of the knowledge will allow the proposition of a parametric model based on the Bionics for the initial phase of inspiration and design of alternatives of the product design.
9

3D Teleconferencing : The construction of a fully functional, novel 3D Teleconferencing system / 3D Telekonferens : Konstruktionen av ett nytt, operativt 3D Teleconferanssystem

Lång, Magnus January 2009 (has links)
<p>This report summarizes the work done to develop a 3D teleconferencing system, which enables remote participants anywhere in the world to be scanned in 3D, transmitted and displayed on a constructed 3D display with correct vertical and horizontal parallax, correct eye contact and eye gaze. The main focus of this report is the development of this system and especially how to in an efficient and general manner render to the novel 3D display. The 3D display is built out of modified commodity hardware and show a 3D scene for observers in up to 360 degrees around it and all heights. The result is a fully working 3D Teleconferencing system, resembling communication envisioned in movies such as holograms from Star Wars. The system transmits over the internet, at similar bandwidth requirements as concurrent 2D videoconferencing systems.</p> / Project done at USC Institute for Creative Technologies, LA, USA. Presented at SIGGRAPH09.
10

Applicability of three dimensional surface scanning to age-at-death estimations based on the human pubic symphysis

Gray, Adam 24 August 2011 (has links)
The application of 3D laser scanning to the analysis of human skeletal remains provides the opportunity for new methodological approaches, including for the assessment of age at death. The focus of this new perspective revolves around the question of whether morphological development of skeletal features can be captured with quantitative measurements taken from 3D scanned representations of physical specimens, with the aims of adding an increased level of accuracy and precision over currently employed age estimations methods that focus on visual, and often subjective, assessments based comparisons with plaster casts and written descriptions. The current research was conducted to determine if specific morphological features of the pubic symphysis could be isolated and quantified on 3D models, and whether these measurements captured the general age related trends of symphyseal development. Using CAD software, each symphyseal face was divided into half and quadrant specific sections in an attempt to better capture the development of symphyseal morphology. A sample of left male pubic symphyses (n = 40) scanned from a well-documented collection of known-age individuals (Coimbra Identified Skeletal Collection) was selected for this study. Seven symphyseal features were identified from the Suchey-Brooks method unisex age phase descriptions. Eight measurements were generated to quantify these features. The data for each feature was subjected to linear regression analyses to test for statistical correspondence to known chronological age at death. Rim completeness, billowing height and area, and depth of symphyseal face depression demonstrated the strongest relationships with chronological age, while curvature of the ventral rampart and the angle of the dorsal aspect, showed significant but weak relationships with known age. Degree of dorsal lipping and dorsal rampart curvature showed no relationship with age. The results of the study suggest that quantitative assessments of morphological changes at the pubic symphysis are possible and therefore can potentially add further insights into age at death estimations based on the pubic symphysis, as measurements taken within CAD software are far more precise than traditional measuring implements. This study illustrates the potential for 3D imaging to improve the methods of osteological analyses applied particularly in the fields of bioarchaeology and forensic anthropology. / Graduate

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