Method for reading information that has been embedded in an image

摘要

A method for detecting a copy of a composite image that includes a first image and a second image that has information embedded in the second image that will change in appearance when the first and second images are scanned or photocopied. The foregoing is accomplished by scanning the first and second images, and detecting a change in appearance of the second image that indicates the first and second images were scanned or photocopied.