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CATS - Malzbender

Image Based Relighting and Immersive Telepresence
Hewlett-Packard Labs
4/3/2002
4:00pm-5:00pm

In the first part of the talk we present a new form of texture mapping that produces increased photorealism. Coefficients of a biquadratic polynomial are stored per texel, and used to reconstruct the surface color under varying lighting conditions. Like bump mapping, this allows the perception of surface deformations. However, our method is image based, and photographs of a surface under varying lighting conditions can be used to construct these maps. Unlike bump maps, these Polynomial Texture Maps (PTMs) also capture variations due to surface self-shadowing and interreflections, which enhance realism. Surface colors can be efficiently reconstructed from polynomial coefficients and light directions with minimal fixed-point hardware. We have found PTMs useful for producing a number of other effects such as anisotropic and Fresnel shading models and variable depth of focus. Lastly, we present several reflectance function transformations that act as contrast enhancement operators. We have found these particularly useful in the study of ancient archeological clay and stone writings, paleontology and forensics.

The second part of the talk describes an immersive teleconferencing system that we are prototyping. View synthesis methods from computer vision and view dependent texture mapping methods from computer graphics are employed to embed users in a synthetic environment where mobility and eye contact are possible.

Refreshments will be served immediately following the presentation.

Department of Computer Science
University of Colorado Boulder
Boulder, CO 80309-0430 USA
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www.cs.colorado.edu
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