Methods for encoding security documents

• US 6,922,480 B2
• Filed: 07/29/2002
• Issued: 07/26/2005
• Est. Priority Date: 05/08/1995
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B.
• Primary Examiner(s): Johns, Andrew W.
• Application Number:
  US10/208,735
• Publication Number:
  US 20030035565A1
• Time in Patent Office: 1,093 Days
• Field of Search: 382/100, 382/137, 382/232, 380/210, 380/287, 380/54, 713/176, 283/72, 283/92, 283/113, 283/57, 283/901, 283/902
• US Class Current: 382/137
• CPC Class Codes: B29C 45/1418 the inserts being deformed or preformed, e.g. by the injection pressure
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 1/0071 using multiple or alternating watermarks
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G07D 7/0034 using watermarks
• CPC Class Codes: G07D 7/004 using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: H04N 1/00002 Diagnosis, testing or measuring; Detecting, analysing or monitoring not otherwise provided for error detection, error correction or monitoring in digital computers or digital computer components G06F11/00
• CPC Class Codes: H04N 1/00005 relating to image data
• CPC Class Codes: H04N 1/00037 Detecting, i.e. determining the occurrence of a predetermined state H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00092 relating to the original or to the reproducing medium, e.g. imperfections or dirt detecting properties of a sheet H04N1/00681
• CPC Class Codes: H04N 1/00244 with a server, e.g. an internet server fax-servers or the like for store and forward H04N1/324
• 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
• CPC Class Codes: H04N 1/00867 : with additional data, e.g. by adding a warning message details of embedding additional information in an image H04N1/32144
• CPC Class Codes: H04N 1/0087 : with hidden additional data, e.g. data invisible to the human eye
• CPC Class Codes: H04N 1/00875 : Inhibiting reproduction, e.g. by disabling reading or reproduction apparatus
• CPC Class Codes: H04N 1/32144 : embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32203 : Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 : involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32219 : involving changing the position of selected pixels, e.g. word shifting, or involving modulating the size of image components, e.g. of characters H04N1/32224 takes precedence
• CPC Class Codes: H04N 1/32261 : in binary data H04N1/32256 takes precedence
• CPC Class Codes: H04N 1/32304 : Embedding different sets of additional information
• CPC Class Codes: H04N 1/32309 : in colour image data
• CPC Class Codes: H04N 2201/3205 : of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3207 : of an address
• CPC Class Codes: H04N 2201/3226 : of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3233 : of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3239 : using a plurality of different authentication information
• CPC Class Codes: H04N 2201/3246 : of data relating to permitted access or usage, e.g. level of access or usage parameters for digital rights management [DRM] related to still images
• CPC Class Codes: H04N 2201/3249 : data relating to a linked page or object, e.g. hyperlink
• CPC Class Codes: H04N 2201/327 : which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3271 : Printing or stamping
• CPC Class Codes: Y10S 283/901 : Concealed data

Abstract

Line art on a banknote or other security document is slightly changed to effect the encoding of plural-bit digital data (i.e. the banknote is digitally watermarked). When such a banknote is thereafter scanned, the resulting image data can be recognized as corresponding to a banknote by detection of the encoded data. (Alternatively, the image data can be recognized as corresponding to a banknote by machine detection of other forms of watermarking, or by reference to visible structures characteristic of banknotes.) In response to detection of a banknote, the detecting apparatus (e.g., a scanner, photocopier, or printer) can intervene so as to prevent or deter counterfeiting. For example, the apparatus can interrupt a copying operation, and display a message reminding the operator that it is illegal to reproduce currency. Another option is to dial a remote service and report the attempted reproduction of a banknote. Yet another option is to permit the copying, but to insert forensic tracer data (e.g. steganographically encoded binary data) in the resultant copy. The tracer data can memorialize the serial number of the machine that made the copy and/or the date and time the copy was made. To address privacy concerns, such tracer data is not normally inserted in photocopied output, but is so inserted only when the subject being photocopied is detected as being a banknote.

Claims

1. A method of marking a financial instrument to convey plural binary bits, thereby facilitating machine-recognition thereof, the financial instrument having a visible structure formed thereon, the method being characterized in that the marking is not apparent to human observers of the document, yet can be detected from image data generated by visible light scanning of the financial instrument.

2. The method of claim 1 wherein the visible structure comprises at least one of a seal and logo.

3. The method of claim 2 wherein the marking comprises a background pattern formed over at least a portion of the financial instrument.

4. The method of claim 1 wherein the financial instrument comprises a paper document.

5. The method of claim 1, wherein the financial instrument comprises legal tender.

6. The method of claim 1, wherein the financial instrument comprises at least one of a credit card, a debit card and an ATM card.

7. A method of marking a security document to convey plural bit information, thereby facilitating machine-recognition thereof through detection of image data generated by visible light scanning of the security document, the marking including a visible pattern formed over at least a portion of the security document, wherein the pattern does not betray the existence of the plural bit information to casual human observers of the document.

8. The method of claim 7, wherein the security document comprises a financial instrument.

9. The method of claim 7 wherein the visible pattern comprises a background pattern.

10. The method of claim 7 wherein the visible pattern comprises a noise-like pattern.

11. The method of claim 7 wherein the plural bit information is redundantly marked on the security document.

12. The method of claim 7 wherein the visible pattern comprises artwork.