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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.
231

Self-localization in urban environment via mobile imaging facility.

January 2008 (has links)
Chim, Ho Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 58-62). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Objectives --- p.1 / Chapter 1.2 --- Motivations --- p.1 / Chapter 1.3 --- Problem Statement --- p.2 / Chapter 1.4 --- Camera Self-Localization Approaches --- p.3 / Chapter 1.4.1 --- Based on Calibration Patterns --- p.3 / Chapter 1.4.2 --- Based on Self-calibration --- p.3 / Chapter 1.4.3 --- Based on Shape and Motion --- p.4 / Chapter 1.4.4 --- The Proposed Approach - Based on Junctions --- p.5 / Chapter 1.5 --- Thesis Organization --- p.6 / Chapter 2 --- Previous Work --- p.7 / Chapter 2.1 --- Camera Self-Localization --- p.7 / Chapter 2.1.1 --- Parallel Plane Features --- p.7 / Chapter 2.1.2 --- Parallelepiped Features --- p.8 / Chapter 2.1.3 --- Single View Geometric Features --- p.8 / Chapter 2.1.4 --- Shape and Motion --- p.8 / Chapter 2.1.5 --- Other Estimation Methods --- p.9 / Chapter 2.2 --- Feature Correspondences Establishment --- p.9 / Chapter 2.2.1 --- Feature-based Object Recognition --- p.9 / Chapter 2.2.2 --- Model-based Object Recognition --- p.10 / Chapter 3 --- Preliminaries --- p.11 / Chapter 3.1 --- Perspective Camera Model --- p.11 / Chapter 3.2 --- Camera Pose from Point Correspondences --- p.15 / Chapter 3.3 --- Camera Pose from Direction Correspondences --- p.16 / Chapter 4 --- A Junction-based Approach --- p.18 / Chapter 4.1 --- Use of Junction Correspondences for Determining Camera Pose --- p.18 / Chapter 4.1.1 --- Constraints from Point Information --- p.19 / Chapter 4.1.2 --- Constraint from Direction Information --- p.21 / Chapter 4.1.3 --- Junction Triplet Correspondences --- p.22 / Chapter 4.2 --- Extraction of Junctions and Junction Triplets from Image --- p.24 / Chapter 4.2.1 --- Handling Image Data --- p.24 / Chapter 4.2.2 --- Bridging Lines --- p.25 / Chapter 4.2.3 --- """L""-junctions" --- p.26 / Chapter 4.2.4 --- """Y"" and ""Adjunctions" --- p.27 / Chapter 4.2.5 --- Junction Triplets --- p.28 / Chapter 4.3 --- Establishment of the First Junction Triplet Correspondence --- p.30 / Chapter 4.3.1 --- Ordered Junction Triplets from Model --- p.30 / Chapter 4.3.2 --- A Junction Hashing Scheme --- p.31 / Chapter 4.4 --- Establishment of Points Correspondence --- p.33 / Chapter 4.4.1 --- Viewing Sphere Tessellation --- p.33 / Chapter 4.4.2 --- Model Views Synthesizing --- p.35 / Chapter 4.4.3 --- Affine Coordinates Computation --- p.35 / Chapter 4.4.4 --- Hash Table Filling --- p.38 / Chapter 4.4.5 --- Hash Table Voting --- p.38 / Chapter 4.4.6 --- Hypothesis and Confirmation --- p.39 / Chapter 4.4.7 --- An Example of Geometric Hashing --- p.40 / Chapter 5 --- Experimental Results --- p.43 / Chapter 5.1 --- Results from Synthetic Image Data --- p.43 / Chapter 5.2 --- Results from Real Image Data --- p.45 / Chapter 5.2.1 --- Results on Laboratory Scenes --- p.46 / Chapter 5.2.2 --- Results on Outdoor Scenes --- p.48 / Chapter 6 --- Conclusion --- p.51 / Chapter 6.1 --- Contributions --- p.51 / Chapter 6.2 --- Advantages --- p.52 / Chapter 6.3 --- Summary and Future Work --- p.52 / Chapter A --- Least-Squares Method --- p.54 / Chapter B --- RQ Decomposition --- p.56 / Bibliography --- p.58
232

O vôo virtual: metáfora e representação cartográfica tridimensional. / The virtual flight: metaphor and three-dimensional cartographic representation.

Queiroz Filho, Alfredo Pereira de 11 May 2005 (has links)
A proposta deste trabalho é compreender o significado do vôo virtual, avaliar as características envolvidas e buscar rumos que ampliem sua utilidade. O vôo virtual é considerado como uma metáfora do deslocamento aéreo. Por meio de representações computacionais, permite variações seqüenciais de direção e de altitude sobre representações cartográficas tridimensionais. Caracteriza-se como uma interface flexível de apresentação de dados espaciais, que viabiliza a consulta dos seus atributos. O vôo possui um forte apelo visual, que une as características lúdicas dos jogos eletrônicos com o poder de atração das imagens de satélite. Permite o arranjo temático e temporal das informações mapeadas, aumenta as opções de representação (2 e 3D) e oferece uma visão integrada da superfície terrestre horizontal e vertical, proporcionada pelo sistema geocêntrico de coordenadas e pela pirâmide de múltipla resolução, que controla a variação de escala. / This work is prepared for the purposes of understanding the meaning of a virtual flight, to evaluate the characteristics involved and seek new ways to broaden its utility. A virtual flight is considered as a metaphor of air displacement. Through computerized representations, it enables sequential direction and altitude variations over three-dimensional cartographical representations. It is characterized as a flexible spatial data interface, which makes it possible to query its attributes. The flight has strong visual appeal, which combines the ludic characteristics of video games with the power of attraction of satellite images. It enables a thematic and temporal arrangement of mapped information, increases the options of representation (2 and 3D) and offers an integrated view of the land surface horizontal and vertical made possible through the geocentric system of coordinates and the multiple resolution pyramid, which controls the scale variation.
233

Leveraging Text-to-Scene Generation for Language Elicitation and Documentation

Ulinski, Morgan Elizabeth January 2019 (has links)
Text-to-scene generation systems take input in the form of a natural language text and output a 3D scene illustrating the meaning of that text. A major benefit of text-to-scene generation is that it allows users to create custom 3D scenes without requiring them to have a background in 3D graphics or knowledge of specialized software packages. This contributes to making text-to-scene useful in scenarios from creative applications to education. The primary goal of this thesis is to explore how we can use text-to-scene generation in a new way: as a tool to facilitate the elicitation and formal documentation of language. In particular, we use text-to-scene generation (a) to assist field linguists studying endangered languages; (b) to provide a cross-linguistic framework for formally modeling spatial language; and (c) to collect language data using crowdsourcing. As a side effect of these goals, we also explore the problem of multilingual text-to-scene generation, that is, systems for generating 3D scenes from languages other than English. The contributions of this thesis are the following. First, we develop a novel tool suite (the WordsEye Linguistics Tools, or WELT) that uses the WordsEye text-to-scene system to assist field linguists with eliciting and documenting endangered languages. WELT allows linguists to create custom elicitation materials and to document semantics in a formal way. We test WELT with two endangered languages, Nahuatl and Arrernte. Second, we explore the question of how to learn a syntactic parser for WELT. We show that an incremental learning method using a small number of annotated dependency structures can produce reasonably accurate results. We demonstrate that using a parser trained in this way can significantly decrease the time it takes an annotator to label a new sentence with dependency information. Third, we develop a framework that generates 3D scenes from spatial and graphical semantic primitives. We incorporate this system into the WELT tools for creating custom elicitation materials, allowing users to directly manipulate the underlying semantics of a generated scene. Fourth, we introduce a deep semantic representation of spatial relations and use this to create a new resource, SpatialNet, which formally declares the lexical semantics of spatial relations for a language. We demonstrate how SpatialNet can be used to support multilingual text-to-scene generation. Finally, we show how WordsEye and the semantic resources it provides can be used to facilitate elicitation of language using crowdsourcing.
234

The automated synchronisation of independently moving cameras.

Pooley, Daniel William January 2008 (has links)
Computer vision is concerned with the recovery of useful scene or camera information from a set of images. One classical problem is the estimation of the 3D scene structure depicted in multiple photographs. Such estimation fundamentally requires determining how the cameras are related in space. For a dynamic event recorded by multiple video cameras, finding the temporal relationship between cameras has a similar importance. Estimating such synchrony is key to a further analysis of the dynamic scene components. Existing approaches to synchronisation involve using visual cues common to both videos, and consider a discrete uniform range of synchronisation hypotheses. These prior methods exploit known constraints which hold in the presence of synchrony, from which both a temporal relationship, and an unchanging spatial relationship between the cameras can be recovered. This thesis presents methods that synchronise a pair of independently moving cameras. The spatial configuration of cameras is assumed to be known, and a cost function is developed to measure the quality of synchrony even for accuracies within a fraction of a frame. A Histogram method is developed which changes the approach from a consideration of multiple synchronisation hypotheses, to searching for seemingly synchronous frame pairs independently. Such a strategy has increased efficiency in the case of unknown frame rates. Further savings can be achieved by reducing the sampling rate of the search, by only testing for synchrony across a small subset of frames. Two robust algorithms are devised, using Bayesian inference to adaptively seek the sampling rate that minimises total execution time. These algorithms have a general underlying premise, and should be applicable to a wider class of robust estimation problems. A method is also devised to robustly synchronise two moving cameras when their spatial relationship is unknown. It is assumed that the motion of each camera has been estimated independently, so that these motion estimates are unregistered. The algorithm recovers both a synchronisation estimate, and a 3D transformation that spatially registers the two cameras. / Thesis (Ph.D.) - University of Adelaide, School of Computer Science, 2008
235

The effect of three-dimensional art works made by adults on children's construction of three-dimensional form

Stewart, Robyn, n/a January 1987 (has links)
Many studies of children's learning in Art education have focused on the young child working in two-dimensional processes. This study examined ways in which emerging-adolescents worked three dimensionally with clay. The purpose of the study was to discover whether the introduction of adult models of three-dimensional form would affect the way the child perceived and constructed threedimensional form. These models were presented as perceptual frames of reference related to the problem confronting the child. The development of perceptual differentiation skills and perceptual, manipulative and conceptual modes of learning underpin this investigation. Four intact classrooms of 12 year olds were studied and the results were examined by a panel of judges. A rating scale devised by the author was applied to each model. The scale was designed to measure five aspects of three-dimensional form. Results indicated that three-dimensional art works made by adults do affect aspects of the way children approach visual problem solving. Implications for the use of such frames of reference in the art classroom and indications of associated motivational and attitudinal changes are presented in the study.
236

An exploration of systematic strategies for representing three-dimensional space on a two-dimensional surface

Jowett, David Unknown Date (has links)
This project explores systematic strategies for establishing a definitive mode of representation in drawing. These strategies are considered in the context of the subjectivities and contingencies of perceptual experience, the mediation of that experience and inherent limitations in representational language. The aim is to explore the possibilities of constructing two-dimensional artworks which serve to define or investigate perceptual processes, perspective devices and spatial relationships.
237

Feature extraction from two consecutive traffic images for 3D wire frame reconstruction of vehicle

He, Xiaochen. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
238

Preliminary Characterisation of Low-Temperature Bonded Copper Interconnects for 3-D Integrated Circuits

Leong, Hoi Liong, Gan, C.L., Pey, Kin Leong, Tsang, Chi-fo, Thompson, Carl V., Hongyu, Li 01 1900 (has links)
Three dimensional (3-D) integrated circuits can be fabricated by bonding previously processed device layers using metal-metal bonds that also serve as layer-to-layer interconnects. Bonded copper interconnects test structures were created by thermocompression bonding and the bond toughness was measured using the four-point test. The effects of bonding temperature, physical bonding and failure mechanisms were investigated. The surface effects on copper surface due to pre-bond clean (with glacial acetic acid) were also looked into. A maximum average bond toughness of approximately 35 J/m² was obtained bonding temperature 300 C. / Singapore-MIT Alliance (SMA)
239

Volume analysis and visualization /

Khare, Ankit. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 48-51). Also available on the World Wide Web.
240

A multiresolutional approach for large data visualization

Wang, Chaoli, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 116-123).

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