The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 19, 1994
Filed:
Dec. 26, 1990
Andrew S Glassner, Mountain View, CA (US);
Xerox Corporation, Stamford, CT (US);
Abstract
A method for constructing object-local sampling histories for efficient path tracing. The present invention provides a technique for efficiently producing computer generated two-dimensional synthetic images of three-dimensional scenes. Objects within in the scene (10) are assigned packs (30,36) containing one or more elements (32,38). For light reflective objects (19,O1), each element (32) of the object's pack (30) represents a region of the object's reflection hemisphere (30) through which incident light is equally likely to be reflected. For light transmissive objects (19,O1), the elements (32) represent analogous regions of equal transmission. For light emitting objects (L1), each element (38) of the object's pack (36) represents a region of equal light emission probability. In a recursive ray or path tracing algorithm, the pack (30,26) of each object (O1,L1) is interrogated to provide unused elements (32a,38a) corresponding to directional regions for sending transmitted (T1) or reflected (R1) backward-going rays, or for emitting illumination rays (I1 ). As each unused element (32a,38a) of an object's pack (30,36) is used, that element is marked as unavailable (32b,38b) until are elements are marked, when all elements are then unmarked (32a,38a) and the element selection process continues. The methods of the present invention insure that rays are directed through the scene in an image synthesis algorithm in directions most important for scene reconstruction, but ensuring that full coverage of all directions is maintained.