Generating 3D thumbnails for 3D contents

Ankara : The Department of Computer Engineering and the Institute of Engineering and Science of Bilkent University, 2010.Thesis (Master's) -- Bilkent University, 2010.Includes bibliographical references leaves 74-80.Creating effective thumbnails is a challenging task because finding important features and preserving the quality of the content is difficult. Additionally, as the popularity of 3D technologies is increasing, the usage area of 3D contents and the 3D content databases are expanding. However, for these contents, 2D thumbnails are insufficient since the current methods for generating them do not maintain the important and recognizable features of the content and give the idea of the content. In this thesis, we introduce a new thumbnail format, 3D thumbnail that helps users to understand the content of the 3D graphical scene or 3D video + depth by preserving the recognizable features and qualities. For creating 3D thumbnails, we developed a framework that generates 3D thumbnails for different 3D contents in order to create meaningful and qualified thumbnails. Thus, the system selects the best viewpoint in order to capture the scene with a high amount of detail for 3D graphical scenes. On the other hand, this process is different for 3D videos. In this case, by a saliency-depth based approach, we find the important objects on the selected frame of the 3D video and preserve them. Finally, after some steps such as placement, 3D rendering etc., the resulting thumbnails give more glorified information about the content. Finally, several experiments are presented which show that our proposed 3D thumbnail format is statistically (p <0.05 ) better than 2D thumbnails.Yiğit, YelizM.S

MAC-REALM: A video content feature extraction and modelling framework

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.A consequence of the ‘data deluge’ is the exponential increase in digital video footage, while the ability to find relevant video clips diminishes. Traditional text based search engines are no longer optimal for searching, as they cannot provide a granular search of the content inside video footage. To be able to search the video in a content based manner, the content features of the video need to be extracted and modelled into a content model, which can then act as a searchable proxy for the video content. This thesis focuses on the extraction of syntactic and semantic content features and content modelling, using machine driven processes, with either little or no user interaction. Our abstract framework design extracts syntactic and semantic content features and compiles them into an integrated content model. The framework integrates a four plane strategy that consists of a pre-processing plane that removes redundant data and filters the media to improve the feature extraction properties of the media; a syntactic feature extraction plane that extracts low level syntactic feature and mid-level syntactic features that have semantic attributes; a semantic relationship analysis and linkage plane, where the spatial and temporal relationships of all the content features are defined, and finally a content modelling stage where the syntactic and semantic content features are integrated into a content model. Each of the four planes can be split into three layers namely, the content layer, where the content to be processed is stored; the application layer, where the content is converted into content descriptions, and the MPEG-7 layer, where content descriptions are serialised. Using MPEG-7 standards to produce the content model will provide wide-ranging interoperability, while facilitating granular multi-content type searches. The framework is aiming to ‘bridge’ the semantic gap, by integrating the syntactic and semantic content features from extraction through to modelling. The design of the framework has been implemented into a prototype called MAC-REALM, which has been tested and evaluated for its effectiveness to extract and model content features. Conclusions are drawn about the research output as a whole and whether they have met the objectives. Finally, future work is presented on how concept detection and crowd sourcing can be used with MAC-REALM

Interfaces for human-centered production and use of computer graphics assets

L'abstract è presente nell'allegato / the abstract is in the attachmen

Actas do 10º Encontro Português de Computação Gráfica

Actas do 10º Encontro Portugês de Computação Gráfica, Lisboa, 1-3 de Outubro de 2001A investigação, o desenvolvimento e o ensino na área da Computação Gráfica constituem, em Portugal, uma realidade positiva e de largas tradições. O Encontro Português de Computação Gráfica (EPCG), realizado no âmbito das actividades do Grupo Português de Computação Gráfica (GPCG), tem permitido reunir regularmente, desde o 1º EPCG realizado também em Lisboa, mas no já longínquo mês de Julho de 1988, todos os que trabalham nesta área abrangente e com inúmeras aplicações. Pela primeira vez no historial destes Encontros, o 10º EPCG foi organizado em ligação estreita com as comunidades do Processamento de Imagem e da Visão por Computador, através da Associação Portuguesa de Reconhecimento de Padrões (APRP), salientando-se, assim, a acrescida colaboração, e a convergência, entre essas duas áreas e a Computação Gráfica. Este é o livro de actas deste 10º EPCG.INSATUniWebIcep PortugalMicrografAutodes

Automatic keyframe selection for high-quality image-based walkthrough animation using viewpoint entropy

The computation of high quality animation sequences is expensive. Generation time for each frame can take a few hours Recently, Image-Based Rendering methods have been proposed to solve this problem. As these techniques obtain new arbitrary views from precomputed ones at low cost, walkthroughs may be computed faster. Consequently, the selection of the precomputed images is a very important step. The initial set of keyframes should fulfill two requirements, it must be small but provide as much information as possible on the scene. In this paper we review several keyframe selection strategies and then we propose a new method based on entropy that achieve similar, and in some cases better, results.Peer Reviewe

Automatic keyframe selection for high-quality image-based walkthrough animation using viewpoint entropy

The computation of high quality animation sequences is expensive. Generation time for each frame can take a few hours Recently, Image-Based Rendering methods have been proposed to solve this problem. As these techniques obtain new arbitrary views from precomputed ones at low cost, walkthroughs may be computed faster. Consequently, the selection of the precomputed images is a very important step. The initial set of keyframes should fulfill two requirements, it must be small but provide as much information as possible on the scene. In this paper we review several keyframe selection strategies and then we propose a new method based on entropy that achieve similar, and in some cases better, results.Peer ReviewedPostprint (published version

Automatic Keyframe Selection for High-Quality Image-Based Walkthrough Animation Using Viewpoint Entropy

The computation of high quality animation sequences is expensive. Generation time for each frame can take a few hours. Recently, Image-Based Rendering methods have been proposed to solve this problem. As these techniques obtain new arbitrary views from precomputed ones at low cost, walkthroughs may be computed faster. Consequently, the selection of the precomputed images is a very important step. The initial set of keyframes should ful ll two requirements, it must be small but provide as much information as possible on the scene. In this paper we review several keyframe selection strategies and then we propose a new method based on entropy that achieve similar, and in some cases better, results

Visitas guiadas através de modelos de volumetria

Esta dissertação tem por fim o estudo de algoritmos que permitem efectuar uma visita guiada a um modelo volumétrico. A visita guiada permite ao utilizador observar todas as partes relevantes do modelo. Assim, expõe-se como seleccionar de forma automática as posições que melhor permitem observar as partes relevantes. Dadas essas posições, mostra-se como criar um percurso que passe por todas elas. O esforço exigido ao utilizador, durante a visita guiada, face à metodologia aplicada, é o mínimo possível, como se este estivesse numa plataforma móvel e alguém empurrasse essa plataforma. Liberto de todas as preocupações associadas à sua deslocação, o utilizador poderá concentrar-se apenas na observação do modelo. É também abordado o caso particular da visita guiada a um modelo representativo de um museu de pintura. As técnicas estudadas são implementadas, tendo sido criado um protótipo que permite efectuar uma visita guiada ao museu. Nessa visita guiada, as peças expostas, que são as partes relevantes do museu, são visualizadas da melhor forma possível, ou seja, de maneira a que sua dimensão e o contexto em que estão inseridas sejam perceptíveis para o utilizador