1. A method for identifying a counterfeit bill in a mobile device, the method comprising the steps of: receiving, by the mobile device, an InfraRed (IR) image of a bill; extracting feature values that represent edges from the IR image; generating a binary image having displayed pixels and non-displayed pixels based on the feature values; generating a corrected image by overlaying the binary image on a pre-stored real bill database and adjusting the binary image to match a predetermined area of the binary image matches to a predetermined area of the real bill database; counting a number of displayed pixels in the corrected image; and determining whether the bill is counterfeit based on the number of displayed pixels in the corrected image.