Apparatus and method for testing bank notes for genuineness using Fourier transform analysis
US5530772A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1994 |
| Grant date | Jun 25, 1996 |
| Priority date | — |
| Expiry date | Dec 21, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/431
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
In apparatus for detecting counterfeit bank-notes, an electronic camera forms a digital representation of a small area of the bank-note. The digital image is stored in an image memory. The Fourier transform of the digital image is then computed and analyzed to determine if it contains high spatial frequency components, and if so, the note is identified as counterfeit. The analyzer may use pattern recognition techniques. In a modification, Fourier transforms of a plurality of small areas are formed and averaged and the average is analyzed. This invention is particularly suitable for identifying counterfeit bank-notes having regular patterns e.g. of lines or dots, therein, such as are produced by color photocopiers or offset lithography printing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.