[pt] A principal motivação para realização deste trabalho é verificar a viabilidade de uso da técnica de mapeamento de textura com relevo em aplicações que exijam interação em tempo real como, por exemplo, jogos eletrônicos. Esta dissertação apresenta uma extensão ao mapeamento de textura com relevo que suporta a representação de efeitos dependentes do ponto de vista e da direção de iluminação, que antes não eram possíveis de serem representados. Além disso, propõe uma forma de paralelizar tal mapeamento entre CPU e GPU (Graphic Processor Unit), utilizando-se para isto da tecnologia de Hyper-Threading. Nesta nova abordagem, cada amostra pertencente a uma textura com relevo é aumentada para incluir três valores escalares representando o vetor normal à superfície reproduzida pela textura. Desta forma, o cálculo de iluminação pode ser efetuado por pixel. A paralelização do processo de mapeamento de textura com relevo demonstra-se favorável uma vez que são obtidos ganhos de até 37% em relação ao tempo de processamento da abordagem convencional. / [en] The main motivation for this work is to verify the feasibility of using relief texture mapping in high-demand real-time applications, such as computer games. This dissertation presents an extension to relief texture mapping that supports the representation of effects that depend of viewpoint and illumination direction, which could not be represented with previous techniques. Moreover, it proposes a way to parallelize relief texture mapping between CPU and GPU, using Hyper-Threading technology. In this new approach, each element that belongs to a relief texture is augmented to include three scalar values representing the normal vector of the reproduced surface. So, the illumination can be calculated per pixel. In the proposed approach, the parallelization of the relief texture mapping represents an acceleration of up to 37% when compared to conventional techniques.

<p>The progression of technical development has yielded practicable camera systems for the acquisition of so called depth maps, images with depth information. </p><p>Images and movies with depth information open the door for new types of applications in the area of computer graphics and vision. That implies that they will need to be processed in all increasing volumes.</p><p>Increased depth image processing puts forth the demand for a standardized data format for the exchange of image data with depth information, both still and animated. Software to convert acquired depth data to such videoformats is highly necessary. </p><p>This diploma thesis sheds light on many of the issues that come with this new task group. It spans from data acquisition over readily available software for the data encoding to possible future applications. </p><p>Further, a software architecture fulfilling all of the mentioned demands is presented. </p><p>The encoder is comprised of a collection of UNIX programs that generate MPEG Z/Alpha, an MPEG2 based video format. MPEG Z/Alpha contains beside MPEG2's standard data streams one extra data stream to store image depth information (and transparency). </p><p>The decoder suite, called TexMPEG, is a C library for the in-memory decompression of MPEG Z/Alpha. Much effort has been put into video decoder parallelization, and TexMPEG is now capable of decoding multiple video streams, not only in parallel internally, but also with inherent frame synchronization between parallely decoded MPEG videos.</p>

The progression of technical development has yielded practicable camera systems for the acquisition of so called depth maps, images with depth information. Images and movies with depth information open the door for new types of applications in the area of computer graphics and vision. That implies that they will need to be processed in all increasing volumes. Increased depth image processing puts forth the demand for a standardized data format for the exchange of image data with depth information, both still and animated. Software to convert acquired depth data to such videoformats is highly necessary. This diploma thesis sheds light on many of the issues that come with this new task group. It spans from data acquisition over readily available software for the data encoding to possible future applications. Further, a software architecture fulfilling all of the mentioned demands is presented. The encoder is comprised of a collection of UNIX programs that generate MPEG Z/Alpha, an MPEG2 based video format. MPEG Z/Alpha contains beside MPEG2's standard data streams one extra data stream to store image depth information (and transparency). The decoder suite, called TexMPEG, is a C library for the in-memory decompression of MPEG Z/Alpha. Much effort has been put into video decoder parallelization, and TexMPEG is now capable of decoding multiple video streams, not only in parallel internally, but also with inherent frame synchronization between parallely decoded MPEG videos.

[pt] O presente trabalho introduz o conceito de impostores com relevo: uma maneira eficiente para representar objetos por imagens em sistemas que requerem visualização em tempo real, especialmente jogos 3D e ambientes de realidade virtual. Para tanto, mesclam-se métodos tipicamente pertencentes à área de renderização baseada em imagens com métodos tradicionais de visualização baseada em geometria. A técnica requer do usuário apenas a modelagem geométrica da entidade a ser representada. Posteriormente o sistema sintetiza texturas com relevo, dinamicamente atualizadas quando necessário, e as visualiza utilizando o método de mapeamento de texturas com relevo. Esta abordagem permite inserir modelos complexos, tanto pela sua natureza geométrica, como pelo seu processo de visualização, no pipeline gráfico em tempo real. Além disso, os impostores com relevo procuram aproveitar o tempo ocioso ou recursos paralelos disponíveis no processador, de forma a balancear a carga de processamento de visualização entre CPU/GPU. Estes impostores também tornam possível a representação de qualquer tipo de objeto geométrico através de mapeamento de texturas com relevo. / [en] The present work introduces the concept of relief impostors: an efficient manner of representing objects by images in systems that require real time rendering, such as 3D games and virtual reality environments. For this purpose, typical methods of image-based rendering are mixed with traditional geometry based rendering methods. This technique only requires from the user the geometric modeling of the entity to be represented. After this, the system synthesizes relief textures, dynamically refreshed when necessary, and renders them using the method of relief texture mapping. This approach allows complex models to be inserted into the real time pipeline system. This complexity arise either from the geometric nature of the model or its process of visualization. Also, the relief impostors try to use the idle time or parallel resources available on the processor, in order to balance the work to be done between the CPU and GPU. Furthermore, they make possible the representation of any kind of geometric object by the relief texture mapping technique.