1. Field of the Invention
The present invention relates to a multi-dimensional texture mapping apparatus, method and program for realizing a high-quality texture mapping technique in the field of three-dimensional computer graphics. For example, it relates to a multi-dimensional texture mapping apparatus, method and program for acquiring texture that varies in accordance with conditions, such as a viewing direction and a direction of a light source, for generating textures of arbitrary sizes corresponding to such conditions, and for mapping texture on a three-dimensional model.
2. Description of the Related Art
Recently, to provide an observer with an image that gives a natural impression, a scheme for generating a texture image of an arbitrary size from a small texture image has been proposed (see Li-Yi Wei, Marc Levoy, “Fast texture Synthesis Using Tree-structured Vector Quantization”, Proceedings SIGGRAPH 2000, pp. 479-488; Andrew Nealen and Marc Alexa, “Hybrid Texture Synthesis”, Eurographics symposium on Rendering, 2003). In this scheme, a texture image of an arbitrary size is scanned with reference to a small original texture image, thereby generating a texture image closer to the original image. Further, another scheme as an application of the scheme has also been proposed, in which a target texture image is prepared in addition to a small reference texture image, thereby generating an image that has the same pattern or design as the target texture image and is close to the material of the small reference texture image.
However, the above conventional texture image generation technique is directed to generation of a single texture image, but not to generation and/or processing of a large number of texture images acquired in a number of viewing directions and/or using a number of light sources. As an apparatus for realizing the latter case, a multi-dimensional texture generation apparatus exists, which utilizes textures acquired or created, for example, in different viewing directions and using different light sources, and generates textures of arbitrary sizes corresponding to the respective conditions. This apparatus can generate a high-quality texture based on different conditions.
However, processing of textures acquired or created, for example, in different viewing directions using different light sources requires an enormous amount of data. Therefore, a technique for compressing texture data in accordance with the features of materials is indispensable. Data compression enables various texture generation techniques to be utilized, and enables a robust and high-quality texture to be created. In addition, when mapping a texture to a three-dimensional model, if a small number of texture samples are utilized, a highly accurate interpolation technique is necessary.
To express the optical characteristic of an object surface that varies in accordance with a viewing direction and a direction of a light source, a large number of texture images acquired in different viewing directions and in different directions of a light source, and an enormous number of computations are required. Therefore, no practical systems are established.
Moreover, since there is no texture generation method for simultaneously processing a large number of texture images, the optical characteristic of an object surface cannot be expressed in a real manner when a texture image of an arbitrary size is varied in accordance with a viewing direction and a direction of a light source.