The growing size of organizations is making it increasingly expensive to attend meetings and difficult to retain what happened in those meetings. Meeting video capture systems exist to support video conferencing for remote participation or archiving for later review, but they have been regarded ineffective. The reason is twofold. Firstly, the conventional way of capturing video using a single static camera fails to capture focus and context. Secondly, a single static view is often monotonous, making the video onerous to review. To address these issues, often human camera operators are employed to capture effective videos with changing views, but this approach is expensive. In this thesis, we argue that camera views can be changed automatically to produce meeting videos effectively and inexpensively. We automate the camera view control by automatically determining the visual focus of attention as a function of time and moving the camera to capture it. In order to determine visual focus of attention for different meetings, we conducted experiments and interviewed television production professionals who capture meeting videos. Furthermore, television production principles were used to appropriately frame shots and switch between shots. The result of the evaluation of the automatic camera control system indicated its significant benefits over conventional static camera view. By applying television production principles various issues related to shot stability and screen motion were resolved. The performance of the automatic camera control based on television production principles also approached the performance of trained human camera crew. To further reduce the cost of the automation, we also explored the application of computer vision and audio tracking. Results of our explorations provide empirical evidence in support of the utility of camera control encouraging future research in this area. Successful application of television production principles to automatically control cameras suggest various ways to handle issues involved in the automation process.

[pt] Com o avanço do poder de processamento gráfico e a popularização dos jogos eletrônicos, começam a surgir novas formas de entretenimento, entre elas a de espectadores de jogos. Os requisitos para o posicionamento de câmera para os espectadores visualizarem os jogos são diferentes dos aplicados aos jogadores. Enquanto a câmera para os jogadores deve atender a requisitos de jogabilidade, a câmera para os espectadores deve explorar diferentes ângulos de visualização a fim de aumentar a imersão no ambiente dos jogos e explorar a emoção das cenas. O cinema já evoluiu toda uma linguagem cinematográfica que potencializa a interpretação de cenas. Pesquisas recentes procuram usar a cinematografia na visualização de jogos. O principal desafio na adaptação da cinematografia para os jogos reside na existência de um ambiente dinâmico, onde não se pode prever o andamento da história. Podemos identificar três módulos para a adaptação da cinematografia em jogos: roteirista, responsável por identificar o que está ocorrendo na cena; diretor/editor, responsável por definir as melhores tomadas para capturar a cena; cinegrafista, responsável por posicionar a câmera no ambiente dinâmico para melhor atender às demandas do módulo diretor/editor. Este trabalho propõe a implementação de um módulo cinegrafista. A partir de requisitos para o posicionamento da câmera oriundos de um módulo externo, propõe-se um modelo de câmera que faz o posicionamento automático da câmera. Os requisitos de posicionamento são expressos em um conjunto de restrições que devem ser atendidas pelo modelo de câmera. A câmera usa um modelo físico baseado em um sistema de partículas regido pelo método de Verlet, empregando o método de relaxação para a convergência do sistema a fim de atender às restrições impostas. Experimentos computacionais demonstram a capacidade do módulo proposto de atender a sofisticadas regras de posicionamento de câmera, baseando-se em composições de restrições simples. Princípios da cinematografia, como enquadramento, posicionamento e movimento de câmeras, e respeito à linha de ação, são facilmente respeitados pelo módulo proposto. / [en] With the evolution in graphics processing power and the popularizationof electronic games, new forms of entertainment, such as being a gamespectator. The requirements for positioning the camera for the spectatorsto view the games are different from those applied to players. The camerafor the players must fulfill playability requirements, while the camera forthe spectators must explore different viewing angles in order to increasethe immersion in the game environment and to explore the thrill of thescenes. The cinema has evolved a whole cinematographic language thatoptimizes the scene interpretation. Recent research has been seeking toapply cinematography to game visualization. The main challenge in theadaptation of the cinematographic language for games lies in the existence ofa dynamic environment in which the storys progress cannot be anticipated.Three modules can be identified to adopt the cinematographic language ingames: screenwriter, responsible for identifying what is happening in thescene; director/editor, responsible for defining the best takes to capture thescene; and cinematographer, responsible for positioning the camera in thedynamic environment to better comply with the director editors demands.The present work proposes the implementation of a cinematographer module.Based on camera position requirements obtained from an external module,we propose a camera model that automatically positions the camera.The positioning requirements are expressed by a set of constraints that mustbe respected by the camera model. The camera uses a physical model basedon a particle system oriented by Verlets method, and employs the relaxationmethod to obtain the systems convergence in order to comply with imposedconstraints. Computational experiments have demonstrated the capacity ofthe proposed module to comply with sophisticated camera positioning rulesbased on compositions of simple constraints. Cinematography principlessuch as framing, camera position and movement, and respecting the line ofaction are easily accomplished by the proposed module.