Portuguese Meeting on Computer Graphics 2001

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https://diglib.eg.org/handle/10.2312/2633256

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    Vision-Based Interaction within a Multimodal Framework
    (The Eurographics Association, 2022) Sá, Vítor; Malerczyk, Cornelius; Schnaider, Michael; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    Our contribution is to the field of video-based interaction techniques and is integrated in the home environment of the EMBASSI project. This project addresses innovative methods of man-machine interaction achieved through the development of intelligent assistance and anthropomorphic user interfaces. Within this project, multimodal techniques represent a basic requirement, especially considering those related to the integration of modalities. We are using a stereoscopic approach to allow the natural selection of d evices via pointing gestures. The pointing hand is segmented from the video images and the 3D position and orientation of the forefinger is calculated. This modality has a subsequent integration with that of speech, in the context of a multimodal interaction infrastructure. In a first phase, we use semantic fusion with amodal input, considering the modalities in a so-called late fusion state.
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    Wavelet Compression and Transmission of Deformable Surfaces over Networks
    (The Eurographics Association, 2022) Calado Lopes, António; Gamito, Manuel; Salles Dias, José Miguel; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    An animation of a deformable surface with fixed topology is formed by a set of connected points (particles), which follow a trajectory over time. The transmission of such an animation is a task that consumes large amounts of bandwidth, as the position of each particle, in each time instant, needs to be transmitted. We propose a wavelet based compression and streaming mechanism that allows the minimization of the size of the animation data, hence decreasing the total transmission time. The proposed transmission scheme, based on the timelocalized feature of the wavelet transform, will be able to stream the animation so that a receiver can immediately view the fraction of the animation received, while wavelet coefficients are still arriving.
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    Estratégias de desenvolvimento de jogos multimedia
    (The Eurographics Association, 2022) Faria Lopes, Pedro; Vasconcelos Moreira, Maria; Pereira, Hugo; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    Com a crescente necessidade de desenvolver projectos multimédia de maior qualidade, em tempos de concretização menores, há que definir critérios que permitam alcançar estes objectivos. Neste trabalho descrevem-se alguns dos critérios encontrados, tanto pelo estudo e análise de projectos já existentes, como pela nossa experiência na concretização de dois projectos, um já concluído e outro em desenvolvimento, na área dos jogos multimédia.
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    Automatic Feature Extraction on Pages of Antique Books Through a Mathematical Morphology Based Methodology
    (The Eurographics Association, 2022) Granado, Isabel; Pina, Pedro; Muge, Fernando; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    This paper presents a mathematical morphology based methodology to identify and extract several components on antique printed books in order to automatically build metadata. These components were previously classified into five different sets (drop capitals, stripes, figures, annotations and text matter) each one characterised by particular geometric features. Based on that assumption several novel algorithms appealing to morphological operators are proposed. The evaluation of the methodology is performed on pages of XVI century books.
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    Visualização interactiva tridimensional em Java3D
    (The Eurographics Association, 2022) Caiado, Bruno; Correia, Luís; Lopes, João Brisson; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    Esta comunicação descreve a concepção e realização em Java/Java3D da aplicação NISVAS para visualização interactiva de conjuntos de dados de grande volume resultantes da simulação numérica de fenómenos complexos. A aplicação, que é portável, visualiza estes dados através de cores, símbolos, vectores e animações. Descrevem- se os objectivos, a arquitectura e a funcionalidade do visualizador, com realce para a realização da interface com o utilizador que é simples, de fácil aprendizagem e suporta utilizadores com diferentes níveis de experiência. As reacções dos utilizadores permitiram concluir que os objectivos propostos foram alcançados, nomeadamente no referente ao desempenho e à simplicidade e flexibilidade de uso. Apresentam-se direcções para a continuação deste trabalho.
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    Interfaces caligráficas RISC
    (The Eurographics Association, 2022) Pereira, João P.; Jorge, Joaquim A.; Branco, Vasco A.; Ferreira, F. Nunes; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    Ao aumento do poder de cálculo das plataformas computacionais na última década não têm correspondido ganhos de usabilidade dos programas de desenho assistido por computador, pese embora o sucesso das chamadas interfaces de tampo de secretária (desktop). Tal deve-se ao facto de os modelos de construção de objectos e cenas tridimensionais reflectirem mais as características e virtudes da representação computacional desses objectos e não o ponto de vista do utilizador. No presente artigo abordamos o problema através da simplificação da interface e número de comandos, construindo incrementalmente imagens complexas recorrendo a uma interface caligráfica de repertório reduzido de comandos. Através do sistema GIDeS procuramos demonstrar que um conjunto simples de formas base e comandos de manipulação permite construir cenas surpreendentemente complexas graças a um paradigma de desenho incremental, satisfação inteligente de restrições e reconhecimento de esboços.
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    Interactive facilities for collaborative feature modelling on the Web
    (The Eurographics Association, 2022) Bidarra, Rafael; Berg, Eelco van den; Bronsvoort, Willem F.; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    Collaborative modeling systems are distributed multiple-user systems that are both concurrent and synchronized, aimed at supporting engineering teams in coordinating their modeling activities. During a collaborative modeling session, several users are connected to each other in order to perform activities, such as design, manufacturing planning or evaluation, together, using some common product data. An interesting research challenge is to develop a collaborative modeling system that offers all facilities of advanced modeling systems to its users. This paper focuses on the interactive modeling facilities required by such collaborative modeling systems. Previous work in the area of collaborative modeling is surveyed, and several techniques for interaction with feature models are presented, ranging from display of sophisticated feature model images to interactive selection facilities, which have been implemented in the web-based collaborative feature modeling system webSPIFF. It has a client-server architecture, with an advanced feature modeling system as a basis of the server, providing feature validation, multiple views and sophisticated visualization facilities. The architecture of webSPIFF, the functionality of the server and the clients, their communication mechanisms, and the distribution of model data is described. In particular, maintenance and synchronization of model data at the clients, and techniques for their effective utilization for enhancing user interaction and collaboration are described. It is shown that a good compromise between interactivity and network load has been achieved, and that indeed advanced modeling with a collaborative system is feasible.
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    Dynamic Algorithm Selection: A New Approach to the Real-Time Rendering of Complex Scenes Problem
    (The Eurographics Association, 2022) Pires, Pedro; Pereira, João; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    This paper presents a novel approach to the real-time rendering of complex scenes problem. Up to the present date, a huge number of acceleration techniques have been proposed, although most are geared towards a specific kind of scene. Instead of using a single, or a fixed set of rendering acceleration techniques, we propose the use of several, and to select the best one based on the current viewpoint. Thus, dynamically adapting the rendering process to the contents of the scene, it is possible to take advantage of all these techniques when they are better suited, rendering scenes that would otherwise be too complex to display at interactive frame rates. We describe a framework capable of achieving this purpose, consisting on a pre-processor and an interactive rendering engine. The framework is geared towards interactive applications were a complex and large scene has to be rendered at interactive frame rates. Finally, results and performance measures taken from our test implementation are given.
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    ARENA and WOXBOT: Some Steps towards the Animation of Cognitive Characters Acting in a Virtual World
    (The Eurographics Association, 2022) Miranda, Fábio R.; Kögler Junior, J.; Lobo Netto, Márcio; Hernandez, E. Del Moral; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    This paper reports some of the results of the WOXBOT / ARENA project on artificial life. This project to build virtual worlds was set initially aimed at the graphic simulation of an arena where WoxBots, small mobile robots, can perform requested tasks while behaving according to their own motivation and reasoning. Each robot is an intelligent agent that perceives the virtual environment via a simulated vision system and reacts moving away from or approaching to the object it sees. The conception and specification of the robots and the environment are being done very carefully to create an open distributed object architecture that can serve as a test bed freely available and ready to use for testing theories in some computational areas such as evolutionary computation, artificial life, pattern recognition, artificial intelligence, cognitive neurosciences and distributed objects architectures. Furthermore, it is a first step towards building a cognitive animated character.
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    Jogos de Guerra e Paz
    (The Eurographics Association, 2022) Batista, Helder; Costa, Vasco; Pereira, João; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    A simulação de ambientes virtuais realistas de grande complexidade e interactividade é um problema complexo a vários níveis. Na parte de visualização as dificuldades prendem-se com as limitações do hardware para apresentar uma cena complexa a ritmos interactivos. Na parte das comunicações o desafio coloca-se na gestão de um número muito elevado de participantes mantendo a coerência do ambiente sem sacrificar o desempenho da simulação. Propomos de seguida soluções que procuram tornar possível a realização de simulações de elevado realismo em equipamentos comuns, de baixo custo, disponíveis actualmente no mercado.
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    Jogo do Galo, Agente de Apoio à Utilização de Jogos por Deficientes Profundos
    (The Eurographics Association, 2022) Pereira, António; Amaro, Ricardo; Paiva, Ana; Lopes, João Brisson; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge
    O projecto apresentado nesta comunicação teve por objectivo realizar e testar um agente autónomo para apoio à utilização de jogos por deficientes profundos. O agente desenvolvido tem como primeiro objectivo a parcial substituição do terapeuta que apoia o utilizador. A sua função é ensinar e manter o utilizador interessado no jogo. Apresenta-se a arquitectura adoptada e as opções tomadas durante a concepção e desenvolvimento realizados, incluindo aspectos como a comunicação com o jogo e os comportamentos com que o agente tenta manter o utilizador motivado e interessado. Os testes de campo realizados permitiram verificar que o emprego de um agente é extremamente benéfico e constatar problemas de que se apresentam soluções para o trabalho que dará continuidade ao agora realizado.
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    Proceedings Info
    (The Eurographics Association, 2022) Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge; Joaquim Madeira; Jorge Salvador Marques; Miguel Salles Dias; Joaquim A. Jorge