Detecting counterfeit banknotes is achieved by directing ultraviolet light at a sample from a source (104) and measuring the level of ultraviolet light reflected from the sample using a first photocell (104) and the amount of fluorescent light generated by the sample using a second photocell (106). The...http://www.google.com/patents/US5918960?utm_source=gb-gplus-sharePatent US5918960 - Detection of counterfeit objects, for instance counterfeit banknotes
