Visualização interativa de modelos 3D realistas na web

Orientador : Prof. Dr. Luciano SilvaCo-orientadora : Profª. Drª. Olga Regina Pereira BellonTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 16/09/2014Inclui referênciasResumo: A visualização 3D remota de objetos culturais é uma ferramenta importante para diversas atividades na área de preservação digital, pois pode minimizar danos causados pelo transporte ou manipulação física dos objetos. Os modelos 3D gerados no processo de digitalização 3D podem auxiliar em restaurações ou na reconstrução física dos objetos. Devido aos avanços das tecnologias para digitalização 3D, os modelos 3D estão cada vez mais precisos. A disponibilização desses modelos para a visualização na web pode ser dificultada por restrições de acesso remoto, como por exemplo espaço de armazenamento, memória, capacidade de processamento e velocidade de conexão disponíveis. Nesse contexto, esta tese se concentra na visualização web interativa de modelos 3D realistas com fidelidade visual requerida ao estudo remoto dos objetos. O framework de visualização 3D baseada na web proposto incorpora a compressão progressiva de modelos 3D coloridos orientada por dados, uma base de dados de apoio à reconstrução 3D progressiva e uma aplicação web para a visualização 3D remota. Ao preservar as cores através do mapeamento de textura, a abordagem de compressão 3D progressiva orientada por dados proposta provê modelos intermediários com boa qualidade visual, principalmente a baixas resoluções. A estrutura do framework possibilita à aplicação suportar acessos simultâneos, além de viabilizar o acesso remoto por computadores e dispositivos móveis com restrição de recursos. A aplicação desenvolvida aproveita os recentes avanços das tecnologias web, proporcionando acesso livre de plugins e melhorando a qualidade da experiência do usuário. A solução proposta foi aplicada aos modelos 3D do conjunto de esculturas chamado "Os Doze Profetas" de Aleijadinho, considerado Patrimônio Mundial pela UNESCO. Através dos resultados experimentais pode-se comprovar que a preservação das cores combinada à reconstrução 3D progressiva é uma estratégia efetiva e apropriada para a visualização interativa de modelos 3D realistas na web. Palavras-chave: Preservação digital. Modelos 3D realistas. Visualização na web. Reconstrução 3D progressiva. Qualidade visual.Abstract: Remote 3D visualization of valuable objects is a very important tool for the accomplishment of digital preservation tasks, since it prevents damages caused both by shipping and physical manipulation. The 3D models generated by 3D scanning may help physical restoration or reconstruction of the objects. Due to advances in 3D scanning technologies, the 3D models are becoming increasingly detailed. The web visualization of these models generated for digital preservation purposes is hampered by storage space, memory and processing restrictions. In this context, this thesis focuses on interactive web visualization of realistic 3D models for the remote study of the objects. The proposed web-based 3D visualization framework incorporates the datadriven progressive compression of colored 3D models, the database to support the progressive 3D reconstruction and a web application for remote 3D visualization. By preserving the colors through texture mapping, the proposed data-driven progressive 3D compression provides intermediate models with good visual quality at low resolutions. The framework enables the web application to support concurrent access, as well as providing access through computers with restricted resources. Our application takes advantages of the recent advances of the web technologies for providing a plugin-free experience. The proposed solution was applied to sculptures of the Twelve Prophets of Aleijadinho, considered World Heritage by UNESCO. The experimental results shows that the color preservation combined with progressive 3D reconstruction is an effective and appropriate strategy for interactive visualization of realistic 3D models on the web. Keywords: Digital preservation. Realistic 3D models. Web-based visualization. Progressive 3D reconstrution. Visual Quality

Management of spatial data for visualization on mobile devices

Vector-based mapping is emerging as a preferred format in Location-based Services(LBS), because it can deliver an up-to-date and interactive map visualization. The Progressive Transmission(PT) technique has been developed to enable the ecient transmission of vector data over the internet by delivering various incremental levels of detail(LoD). However, it is still challenging to apply this technique in a mobile context due to many inherent limitations of mobile devices, such as small screen size, slow processors and limited memory. Taking account of these limitations, PT has been extended by developing a framework of ecient data management for the visualization of spatial data on mobile devices. A data generalization framework is proposed and implemented in a software application. This application can signicantly reduce the volume of data for transmission and enable quick access to a simplied version of data while preserving appropriate visualization quality. Using volunteered geographic information as a case-study, the framework shows exibility in delivering up-to-date spatial information from dynamic data sources. Three models of PT are designed and implemented to transmit the additional LoD renements: a full scale PT as an inverse of generalisation, a viewdependent PT, and a heuristic optimised view-dependent PT. These models are evaluated with user trials and application examples. The heuristic optimised view-dependent PT has shown a signicant enhancement over the traditional PT in terms of bandwidth-saving and smoothness of transitions. A parallel data management strategy associated with three corresponding algorithms has been developed to handle LoD spatial data on mobile clients. This strategy enables the map rendering to be performed in parallel with a process which retrieves the data for the next map location the user will require. A viewdependent approach has been integrated to monitor the volume of each LoD for visible area. The demonstration of a exible rendering style shows its potential use in visualizing dynamic geoprocessed data. Future work may extend this to integrate topological constraints and semantic constraints for enhancing the vector map visualization

Receiver-driven view-dependent streaming of progressive mesh

10.1145/1496046.1496049Proceedings of the International Workshop on Network and Operating System Support for Digital Audio and Video9-1

Modélisation et distribution adaptatives de grandes scènes naturelles

Cette thèse traite de la modélisation et la diffusion de grandes scènes 3D naturelles. Nous visons à fournir des techniques pour permettre à des utilisateurs de naviguer à distance dans une scène 3D naturelle, tout en assurant la cohérence botanique et l'interactivité. Tout d'abord, nous fournissons une technique de compression multi-résolution, fondée sur la normalisation, l'instanciation, la décorrélation, et sur le codage entropique des informations géometriques pour des modèles de plantes. Ensuite, nous étudions la transmission efficace de ces objets 3D. L'algorithme de paquétisation proposé fonctionne pour la plupart des représentations multi-résolution d'objet 3D. Nous validons les techniques de paquétisation par des expériences sur un WAN (Wide Area Network), avec et sans contrôle de congestion (Datagram Congestion Control Protocol). Enfin, nous abordons les questions du streaming au niveau de la scène. Nous optimisons le traitement des requêtes du côté serveur en fournissant une structure de données adaptée et nous préparons le terrain pour nos travaux futurs sur l'évolutivité et le déploiement de systèmes distribués de streaming 3D. ABSTRACT : This thesis deals with the modeling and the interactive streaming of large natural 3D scenes. We aim at providing techniques to allow the remote walkthrough of users in a natural 3D scene ensuring botanical coherency and interactivity.First, we provide a compact and progressive representation for botanically realistic plant models. The topological structure and the geometry of the plants are represented by generalized cylinders. We provide a multi-resolution compression scheme, based on standardization and instantiation, on difference-based decorrelation, and on entropy coding. Then, we study efficient transmission of these 3D objects. The proposed packetization scheme works for any multi-resolution 3D representation. We validate our packetization schemes with extensive experiments over a WAN (Wide Area Network), with and without congestion control (Datagram Congestion Control Protocol). Finally, we address issues on streaming at the scene-level. We optimize the viewpoint culling requests on server-side by providing an adapted datastructure and we prepare the ground for our further work on scalability and deployment of distributed 3D streaming systems