The invention provides a method and apparatus for obtaining a range image of an object. The method includes the act of "albedo normalization", i.e., removing the effects of object reflectance using a structured illumination image of the object and a uniform illumination image of the object to provide...http://www.google.com/patents/US5878152?utm_source=gb-gplus-sharePatent US5878152 - Depth from focal gradient analysis using object texture removal by albedo normalization
