Patent ID: 8139208

Claim:
A system for automatically detecting the presence of a transparent window security feature in a bank note, the system comprising: a conveyance device for transporting a bank note along a defined path; at least one optical detection device, the optical detection device comprising a plurality of optical transmitters proximate one side of the defined path with corresponding optical receivers proximate the other side of the defined path; at least one ultrasonic detection device, the ultrasonic detection device comprising a plurality of ultrasonic transmitters proximate one side of the defined path with corresponding ultrasonic receivers proximate the other side of the defined path; at least one computing device operably coupled with the optical detection device and the ultrasonic detection device, wherein the computing device is capable of executing machine-readable program instructions, the program instructions comprising: determining from the output of the optical detection device the presence of an optical abnormality in the bank note; determining from the output of the ultrasonic detection device the presence of an ultrasonic abnormality in the bank note; and determining the presence of a transparent window feature based upon the results of the optical abnormality determination and the ultrasonic abnormality determination.