Computer graphics processing and selective visual display system – Computer graphics processing – Three-dimension
Reexamination Certificate
1998-12-01
2001-06-12
Zimmerman, Mark (Department: 2671)
Computer graphics processing and selective visual display system
Computer graphics processing
Three-dimension
Reexamination Certificate
active
06246416
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to generating and displaying computer images which depict reflected light, and more particularly to a method for simulating the appearance of an anisotropic surface as it reflects light towards a viewer.
2. Related Art
The interaction of light with surfaces has proven to be one of the most complicated and fundamental problems in computer graphics. Considerable research has addressed simulation of light reflected from isotropic surfaces. Models for computer graphic simulation of anisotropic reflection (i.e., reflection of light from rough surfaces) have also been proposed, but are based on either non-physical reflection functions obtained using numerical simulations, or are estimated from experimental data. None of the existing anisotropic models are based on the known physical properties of light. Yet, a physics based approach would be the most appropriate for simulating the natural reflection of light from an anisotropic surface. Such an approach would allow simulation of the image that a viewer would see of light reflected from such a surface. Moreover, in the case of anisotropic surfaces having periodic profiles, the reflection of light from such surfaces has never been modeled in computer graphics. Hence there is a need for a physics-based method by which light, reflected from an anisotropic surface, can be simulated in a computer graphics environment.
SUMMARY OF THE INVENTION
The invention provides a method for performing computer graphic simulation of an anisotropic surface reflecting light towards a viewer. First, the data necessary to calculate the amount of light reflected from each point of the anisotropic surface toward the viewer is obtained. This data includes a statistical description of the surface, as well as information about the light and its directions of incidence and reflection. The data is then sent to a renderer, which calculates the amount of light reflected from each point of the anisotropic surface toward the viewer. An image is then created, based on the calculated values.
The calculation step is performed with the aid of a model that is derived from wave physics. The model also relies on a statistical, probabilistic description of the anisotropic surface, a description which treats the height of any given point on the surface as a random variable. In cases where the surface is anisotropic but has a more periodic profile, a variation of this model can be used.
The invention has the feature of requiring relatively few parameters as input to the calculation step.
The invention has the additional feature of being suited to a physics-based renderer, since the model takes into account wave dependent phenomena.
The invention has the advantage of being applicable to a wider range of surfaces than those considered in previous models.
The invention has the further advantage of being relatively easy to implement, since the calculation step is only moderately complex.
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Cao Huedung X.
Silicon Graphics Inc.
Sterne Kessler Goldstein & Fox P.L.L.C.
Zimmerman Mark
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