Patent ID: 7103206

Claim:
A doubles detection system for detecting doubled documents, the system comprising: at least one light source disposed on a first side of a test document; at least one reflected light sensor disposed along the first side of the test document, and adapted to generate at least one reflected light signal; at least one transmitted light sensor disposed along a second side of the test document, and adapted to generate at least one transmitted light signal; a memory storing at least one master reflected light value and at least one master transmitted light value; and a processor adapted to (1) receive the reflected light signal, (2) generate a reflected light value for the test document, (3) calculate a reflectance ratio between the reflected light value of the test document and the master reflected light value, (4) receive the transmitted light signal, (5) generate a transmitted light value for the test document, (6) adjust the master transmitted light value based on the reflectance ratio, (7) compare the adjusted master transmitted light value to the transmitted light value for the test document, and (8) generate a doubles signal if the comparison of the adjusted master transmitted light value with the transmitted light value for the test document indicates that more than one document is present.