Patent Document ID: 20040041809
Application ID: 10230888
Patent Status: 0

Claim One:
1. A method of deriving the reflectance function of an object model under a variety of lighting conditions, the object model comprising a plurality of surfaces, each of the surfaces defining a normal vector pointing perpendicularly outward, the method comprising the steps of: (a) rendering, for a given orientation of the object model, a plurality of images produced by the object model when illuminated by each of a plurality of spherical harmonic components of incident light, wherein said rendering comprises: (i) calculating the intensity of incident light components upon the object model, relative to the normal at each surface; (ii) calculating the intensity of light components diffusely reflected by the model toward the observer; (iii) calculating the intensity of light components off-specularly reflected toward the observer, relative to the observer's angle with respect to the angle of maximum specular reflection; and (b) defining a reflectance function for the object as a linear combination of said plurality of images.