A currency discriminator for determining the denomination of a bank note or the like is disclosed. It includes a source of light directed at the note to be identified. A 2 mm.times.80 mm stripe is illuminated and the reflected light from the illuminated area is measured by a detector and converted into a digital representation. Synchronizing hardware permits 72 samples, each from a 2 mm.times.80 mm area, to be generated as a bank note is moved past the illuminator. The digital representations are then utilized to develop a four bit correlation number N where each bit is a one if (P.sub.n >P.sub.n-2), (P.sub.n >P.sub.n-4), (p.sub.n >P.sub.n-6), and (P.sub.n >P.sub.n-8) where P.sub.n is the present sample and P.sub.n-2, for example, is the second previous sample. The correlation number N is then compared with the corresponding number in a master list for notes of different denomination. A correlation count is incremented for each denomination where a comparison is found between the actual correlation number N and the number N.sub.x in the list where x represents a note denomination. If the ratio of the highest correlation count for one bank note to the next highest correlation count is equal to or greater than 1.28 and the larger correlation count is at least 28, the bank note is identified.