Patent ID: 7446777

Claim:
A method for computing a plurality of surface descriptors for a closed surface, each surface descriptor being encoded with a property of the closed surface, the method comprising the steps of: a) providing a triangulated model of the closed surface including a plurality of triangles, each triangle having: three vertices, each vertex having a corresponding property value of the property; three edges, each edge connecting a pair of the three vertices; and a planar surface bounded by the three edges; b) selecting a plurality of random points within the closed surface; c) generating, in parallel, a set of surface descriptors originated from each of the plurality of random points using a ray bouncing algorithm, wherein: for each of the plurality of random points, the ray bouncing algorithm includes: c1) tracing the ray from the random point in a random direction; c2) determining the intersected planar surface of the intersected triangle of the plurality of triangles of the closed surface intersected by the ray; c3) determining the point of intersection and an angle of incidence between the ray and the first planar surface; c4) calculating the estimated property value at the point of intersection; c5) determining the ray length using the point of intersection and a previous point of intersection; c6) determining one of the plurality of surface descriptors; c7) incrementing an iteration number; c8) when the iteration number is less than a predetermined convergence testing number; determining a bounce direction using the angle of incidence between the ray and the intersected planar surface; tracing a new ray from the point of intersection in the bounce direction; and repeating steps (c2), (c3), (c4), (c5),(c6), (c7), and (c8); and c9) when the iteration number is equal to the predetermined convergence testing number, setting the iteration number to zero and continuing to step (d); and each surface descriptor is determined using: a ray length of a ray traced by the ray bouncing algorithm; and an estimated property value at a point of intersection between the traced ray and an intersected planar surface of an intersected triangle of the plurality of triangles, the estimated property value calculated using the corresponding property values of the property at the three vertices of the intersected triangle; d) determining whether a distribution of the plurality of sets of surface descriptors converge using a convergence algorithm; e) repeating steps (c) and (d) until the distribution of the plurality of surface descriptors is determined to converge in step (d); and f) storing the converged distribution of the plurality of surface descriptors.