Patent ID: 8368879

Claim:
A system comprising: a conveyance device for transporting a bank note along a path; at least one optical detection device; at least one ultrasonic detection device; 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/or the ultrasonic abnormality determination, wherein the presence of a transparent window is determined when an optical abnormality is determined to be present and an ultrasonic abnormality is determined not to be present.