Detection and deterrence of counterfeiting of documents with tokens characteristic color and spacing

• US 6,343,204 B1
• Filed: 08/25/1999
• Issued: 01/29/2002
• Est. Priority Date: 08/25/1999
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Yang, Xuguang
• Primary Examiner(s): GRAINGER, QUANA MASHELL
• Application Number:
  US09/382,429
• Time in Patent Office: 888 Days
• Field of Search: 399/366, 399/17, 399/45, 382/135, 382/137, 382/165, 358/1.9
• US Class Current: 399/366
• CPC Class Codes: G07D 7/20 Testing patterns thereon G07D7/004, G07D7/005 take precedence
• CPC Class Codes: H04N 1/00846 based on detection of a dedicated indication, e.g. marks or the like
• CPC Class Codes: H04N 1/00859 Issuing an alarm or the like

Abstract

Detection and deterrence of counterfeiting permits one to make legitimate color copies without introducing visual artifacts or experiencing substantial processing delays. An efficient counterfeit deterrence is enabled by the use of an hierarchic detection scheme, in which the majority of documents are classified as free of suspicion using a simple token detection algorithm that imposes a negligible computational burden. The remainder of documents, which are labeled as suspicious, receive analysis by one or more additional detection algorithms. If the suspicious document is identified as being a secure document, this will lead to printing with selectively deteriorated service or complete denial of service. For one embodiment, tokens having a characteristic color (or colors) and spacing, are incorporated into the design of frequently counterfeited documents. The scheme uses a color look-up table (LUT) to detect an initial token having the characteristic color. Upon detection of an initial token, a search is performed based on the expected token spacing in order to locate one or more additional tokens, and to thereby verify that printing of a counterfeit is being attempted. Conventional tests for counterfeit documents can also be used as a further, higher level test. A particularly effective higher level detector uses the locations of the detected tokens to determine orientation so that the suspected area can be compared with a corresponding portion of a secure document on a pixel-by-pixel basis. The invention has negligible impact on the time to render a page and negligible effect on general images and documents, while denying printing or generating visible artifacts on banknote or other secure document images. The scheme can be deployed in a printer driver with no hardware changes and can be adjusted to arrive at a compromise that allows reasonable detection, while causing minimal effect on legitimate users. Furthermore, this method can provide a visible indicator that currency is not counterfeit. Moreover, so long as the characteristic color and spacing of the tokens does not change, no alteration is required for a new series of notes.

Claims

1. An apparatus for deterring counterfeiting of documents, the apparatus comprising:

a first-level detector adapted to detect an initial token having a characteristic color and to thereby quickly eliminate from suspicion a majority of types of the documents without the initial token as legitimate while identifying a minority of types of the documents with the initial token as potentially counterfeit documents;

a second-level detector adapted to further test the potentially counterfeit documents identified by the first-level detector to search for a second token spaced at one of a set of one or more predetermined distances from the initial token, such that detection of the second token can verify which of the potentially counterfeit documents are counterfeit copies; and

an alarm adapted to signal detection of the counterfeit documents by the second-level detector.

2. The apparatus as set forth in claim 1, wherein there are at least two of the predetermined distances, the second-level detector comprising:

a third-level detector adapted to further test the potentially counterfeit documents identified by the second-level detector to search for a third token, spaced at a different predetermined distance from the initial token, than the distance between the initial token and the second token, such that detection of the third token can verify which of the potentially counterfeit documents are counterfeit copies.

3. The apparatus as set forth in claim 2, wherein the predetermined distances increase by integral multiples of a predetermined amount.

4. The apparatus as set forth in claim 1, the second-level detector comprising:

a third-level detector adapted to use orientation information, derived from the initial and second token locations, to compare a portion of the secure document to a corresponding portion of the potentially counterfeit document to further test the potentially counterfeit documents identified by the second-level detector, such that detection of a match between the portion of the secure document and the potentially counterfeit document can verify which of the potentially counterfeit documents are counterfeit copies.

5. The apparatus as set forth in claim 1, wherein the first-level detector comprises:

a color detector adapted to detect look-up in a color look-up table of pixels having a color corresponding to the characteristic color, the pixels being part of a captured image to be printed.

6. The apparatus as set forth in claim 5, wherein the look-up table converts from a first color space value of the captured image to a second color space value of the page to be printed.

7. The apparatus as set forth in claim 1, wherein the alarm signals detection of the counterfeit documents by denying printing.

8. The apparatus as set forth in claim 1, wherein the alarm signals detection of the counterfeit documents by degrading printing.

9. The apparatus as set forth in claim 1, comprising a printer to print a page to be printed.

10. The apparatus as set forth in claim 1, comprising a capture device to capture an image of the document to be printed.

11. A method for deterring counterfeiting of documents, the method comprising the steps of:

first-level detection to detect an initial token having a characteristic color and to thereby quickly eliminate from suspicion a majority of types of the documents without the initial token as legitimate while identifying a minority of types of the documents with the initial token as potentially counterfeit documents;

second-level detection to further test the potentially counterfeit documents identified by the first-level detection to search for a second token spaced at one of a set of one or more predetermine distances from the initial token, such that detection of the second token can verify which of the potentially counterfeit documents are counterfeit copies; and

signaling detection of the counterfeit documents by the second-level detector.

12. The method as set forth in claim 11, wherein there are at least two of the predetermined distances, the second-level detection comprising the step of:

third-level detection to further test the potentially counterfeit documents identified by the second-level detection to search for a third token spaced at a different predetermined distance from the initial token than the distance between the initial token and the second token, such that detection of the third token can verify which of the potentially counterfeit documents are counterfeit copies.

13. The method as set forth in claim 12, wherein the predetermined distances increase by integral multiples of a predetermined amount.

14. The method as set forth in claim 11, the second-level detection comprising the step of:

third-level detection using orientation information, derived from the initial and second token locations, to compare a portion of the secure document to a corresponding portion of the potentially counterfeit document to further test the potentially counterfeit documents identified by the second-level detection, such that detection of a match between the portion of the secure document and the potentially counterfeit document can verify which of the potentially counterfeit documents are counterfeit copies.

15. The method as set forth in claim 11, wherein the first-level detection comprises the step of:

color detection to detect look-up in a color look-up table of pixels having a color corresponding to the characteristic color, the pixels being part of a captured image to be printed.

16. The method as set forth in claim 15, wherein the look-up table converts from a first color space value of the captured image to a second color space value of the page to be printed.

17. The method as set forth in claim 11, wherein the detection of the counterfeit documents is signaled by denying printing.

18. The method as set forth in claim 11, wherein the detection of the counterfeit documents is signaled by degrading printing.

19. The method as set forth in claim 11, comprising the step of printing a page to be printed.

20. The method as set forth in claim 11, comprising the step of capturing an image of the document to be printed.