SYSTEMS AND METHODS FOR AUTHENTICATING AND VERIFYING DOCUMENTS

• US 20030128375A1
• Filed: 12/19/2002
• Published: 07/10/2003
• Est. Priority Date: 01/07/2002
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: RUHL, Jan Matthias, GOLDBERG, David, BERN, Marshall W.
• Granted Patent: US 7,268,906 B2
• Time in Patent Office: Days
• US Class Current: 358/1.6
• CPC Class Codes: H04N 1/32128 attached to the image data, e.g. file header, transmitted message header, information on the same page or in the same computer file as the image for information embedded in the image H04N1/32144
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3235 Checking or certification of the authentication information, e.g. by comparison with data stored independently
• CPC Class Codes: H04N 2201/3236 Details of authentication information generation

Abstract

Abstract of the Disclosure

Xerox Docket No. D/A0037QDocument authentication is accomplished by acquiring document image data, generating a set of features of the document, and generating an assist channel that includes information on how to generate the set of features. The set of features and the assist channel are digitally signed and then append to the document. Document verification is accomplished by acquiring document image data and verifying the signature. If the signature is valid, a set of features of the document is generated using information contained in the assist channel appended to the document. The generated set of features is then compared to the set of features appended on the document. If the sets do not match, the document is determined to have been altered sometimes after the assist channel was appended to the document, i.e., the document is not genuine. Otherwise, the document can be considered to be genuine.

Claims

1. A method for verifying a document containing an image, comprising:

2. The method of claim 1, wherein generating verification document data from the electronic image data comprises generating document feature data based on connected components present in the electronic image data.

3. The method of claim 2, wherein the generated document feature data includes connected component features and position information about the connected components.

4. The method of claim 1, wherein generating verification document data from the electronic image data comprises:

5. The method of claim 4, wherein:

6. The method of claim 1, wherein:

7. The method of claim 6, wherein

8. The method of claim 7, wherein the first value is about 15 pixels, the second value is about 20 pixels and the third value is about 10 pixels.

9. The method of claim 7, wherein matching the identified small connected components to the position information about at least some connected components determined during the authentication process that have a size that is at most about the first value comprises matching the identified small connected components to centroid locations of the connected components determined during the authentication process that have a size that is at most about the first value.

10. The method of claim 6, wherein

11. The method of claim 10, wherein the first value is about 10000 pixels and the second value is about 5000 pixels.

12. The method of claim 10, wherein matching the identified small connected components to the position information about at least some connected components determined during the authentication process that have a size that is at least about the first value comprises matching the identified small connected components to bounding boxes of the connected components determined during the authentication process that have a size that is at least about the first value.

13. The method of claim 1, wherein:

14. The method of claim 13, wherein:

15. The method of claim 14, wherein generating document data from the electronic image data further comprises:

16. The method of claim 1, wherein generating document data from the electronic image data comprises:

17. The method of claim 16, wherein:

18. The method of claim 17, wherein:

19. The method of claim 17, wherein the information about the initial members used during the authentication process comprises centroids of the initial members.

20. The method of claim 1, wherein generating document data from the electronic image data comprises:

21. The method of claim 20, wherein generating the representative value comprises generating a hash value from at least some of the set of connected components using a position-dependent hash function.

22. The method of claim 20, wherein generating the representative value comprises generating a hash value of the positions of at least some of the set of connected components.

23. The method of claim 1, wherein generating document data from the electronic image data comprises:

24. The method of claim 23, wherein generating the representative value comprises generating a hash value from at least some of the set of connected components using a shape-dependent hash function

25. The method of claim 23, wherein generating the representative value comprises generating a hash value of the shapes of at least some of the set of connected components.

26. The method of claim 1, wherein generating the verification document data from the electronic image data based on document data appended to the document comprises modifying the electronic image data based on gray level information contained in the appended document data.

27. The method of claim 26, wherein modifying the electronic image data based on the gray level information comprises modifying the electronic image data based on a gray level histogram contained in the appended document data.

28. The method of claim 26, wherein the image on the document contains alignment marks, the method further comprising:

29. A document verification system that generates verification data for a document containing an image and that determines whether the document is authentic based on the generated verification data and authentication data appended to the document, comprising:

30. The document verification system of claim 29, wherein a first portion of the authentication data includes position information about at least some connected components determined during the authentication process to likely correspond to at least two connected components determined during a verification process, the document verification system further comprising a splitting connected component determining circuit, routine or manager that determines, for each of at least some of the determined connected components, whether that connected component lies within a region around one of the connected component determined during the authentication process to likely correspond to at least two connected components determined during a verification process based on the position information.

31. The document verification system of claim 29, wherein a first portion of the authentication data includes information about connected components used during an authentication process as initial members of groups of connected components used in ordering the determined connected components during the authentication process, the document verification system further comprising a connected components ordering circuit, routine or manager that determines an order of the connected components from a start location of the electronic image data based on information about one of the initial members used during the authentication process contained in the appended document data and determined connected components that have not already been added to an ordered list of the connected components.

32. The document verification system of claim 29, wherein the representative value generating circuit, routine or manager generates, as the at least one representative value based on the generated connected components, a hash value of the positions of a set of the generated connected components.

33. The document verification system of claim 32, wherein the representative value generating circuit, routine or manager generates the hash value of the positions of a set of the generated connected components based on a position-dependent hashing function.

34. The document verification system of claim 29, wherein the representative value generating circuit, routine or manager generates, as the at least one representative value based on the generated connected components, a hash value of shapes of the generated connected components.

35. The document verification system of claim 34, wherein the representative value generating circuit, routine or manager generates the hash value of the positions of a set of the generated connected components based on a shape-dependent hashing function.

36. The document verification system of claim 29, further comprising a document aligning circuit, routine or manager that at least one of aligns the electronic image data to desired dimensions and that modifies gray scale levels of at least some of the image values of the electronic image data.

37. The document verification system of claim 36, wherein, when the document aligning circuit, routine or manager aligns the electronic image data to desired dimensions, the document aligning circuit, routine or manager remaps a number of alignment marks in the electronic image data to predetermined relative locations between the location marks and rescales the electronic image data based on the remapped locations of the alignment marks.

38. The document verification system of claim 36, wherein, when the document aligning circuit, routine or manager modifies the gray scale levels of at least some of the image values of the electronic image data, the document aligning circuit, routine or manager modifies the gray scale levels of at least some of the image values of the electronic image data based on a gray level histogram contained in the appended document data.