Raising Textures to New Heights.(Technology Information)

An innovative technique adds depth to conventional texture maps

Long the de facto standard for adding 2D detail to computer-generated images at minimal computational expense, traditional texture mapping falls flat, literally, when it comes to adding 3D detail to an object's surface. While texture mapping can change the appearance of the surface of an object in terms of its color, it does not affect the perception of three-dimensional shape.

The two-dimensionality of texture-mapped surfaces is particularly evident when the object or scene is being viewed by a moving observer, as in a virtual walk-through, or when the static scene is viewed from an oblique angle.

To raise texture maps to a new level, researchers Manuel Oliveira of the State University of New York at Stony Brook and Gary Bishop of the University of North Carolina at Chapel Hill have developed an image-based rendering technique that enables the representation of 3D surface details and depth.

As we move around the real world, depth variations across a surface or among objects in a scene affect our perception of three-dimensionality because of changes in visibility. For instance, when we walk past a brick wall, some mortar regions may be occluded, then become visible, then become occluded again. This effect, called motion parallax, is absent from a CG wall represented as a single polygon mapped with a 2D brick texture.

The new approach, called relief texture mapping, integrates conventional texture maps with height fields to achieve a more convincing 3D appearance with only small computational load on the processor, as would be the case with detailed geometric models requiring tens of thousands of polygons.

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