An optical paper sorter that uses diffuse reflectance to identify a sheet of paper as either white or non-white. An illuminating fiber optic bundle carries light from a tungsten halogen lamp onto a sheet of paper. A receiving trifurcated fiber optic bundle collects light that is diffusely reflected from...http://www.google.es/patents/US6335501?utm_source=gb-gplus-sharePatente US6335501 - Optical paper sorter
