Forensic verification utilizing forensic markings inside halftones

Patent metadata

Field	Value
Publication number	US-9779298-B2
Application number	US-201615187461-A
Country	US
Kind code	B2
Filing date	Jun 20, 2016
Priority date	Feb 9, 2012
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A forensic verification system extracts a print signature via a print signature extractor from an interior of a halftone contained in an image. The system utilizes a comparator to compare the print signature to a reference signature stored in a registry to determine differences between the print signature and the reference signature. The system utilizes a forensic analyzer to perform a forensic analysis on the signatures based on the comparison to authenticate the image.

First claim

The invention claimed is:

1. A non-transitory computer readable medium comprising computer executable instructions that when executed cause at least one processor to:
extract an interior of a halftone of an image of printed media, wherein at least a portion of the interior of the halftone is encoded with a print signature;
access a reference signature stored in a registry, wherein the reference signature includes encoded payload information, wherein the halftone is encoded with a payload to form a mapping between the print signature and the payload information; and
verify that the printed media is authentic based on a comparison of the print signature and the payload information.

2. The non-transitory computer readable medium of claim 1 , and further comprising computer executable instructions that when executed cause the at least one processor to:
employ the payload information to index the print signature.

3. The non-transitory computer readable medium of claim 1 , and further comprising computer executable instructions that when executed cause the at least one processor to:
encode the halftone with the payload information to forma stegatone.

4. The non-transitory computer readable medium of claim 3 , wherein the halftone is encoded with a unique payload to form a one-to-one mapping between the print signature and the payload information.

5. The non-transitory computer readable medium of claim 3 , wherein the halftone is encoded with a common payload to form a many-to-one mapping between the print signature and the payload information.

6. The non-transitory computer readable medium of claim 1 , and further comprising computer executable instructions that when executed cause the at least one processor to:
preprocess the halftone via a bandpass filter to mitigate low and high frequencies within a captured image.

7. The non-transitory computer readable medium of claim 1 , and further comprising computer executable instructions that when executed cause the at least one processor to:
preprocess the halftone via a difference analyzer that subtracts an image from n aligned captured hardcopy to produce a difference signal image.

8. The non-transitory computer readable medium of claim 1 , and further comprising computer executable instructions that when executed cause the at least one processor to:
process the halftone via a subdivide area processor that uses an equi-spaced grid to segment the halftone into smaller processing portions.

9. The non transitory computer readable medium of claim 8 , and further comprising computer executable instructions that when executed cause the at least one processor to:
process the halftone according to concentric regions of an image.

10. The non-transitory computer readable medium of claim 8 , and further comprising computer executable instructions that when executed cause the at least one processor to:
produce a print signature with an area code generator based on output from the subdivide area processor.

11. The non-transitory computer readable medium of claim 10 , and further comprising computer executable instructions that when executed cause the at least one processor to:
determine a normalized variance for each processing portion generated by the subdivide area processor.

12. A method, comprising:
recovering a print signature from an interior of a halftone of a captured, image of printed media, wherein the halftone is encoded with the print signature;
comparing the print signature to payload information encoded in a reference signature stored in a registry, wherein the halftone is encoded with a payload to form a mapping between the print signature and the payload information; and
verifying that the printed media is authentic based on the comparison.

13. The method of claim 12 , and further comprising:
performing bandpass filtering or digital subtraction on a stegatone formed by encoding the halftone with the payload information; and
subdividing the stegatone.

14. The method of claim 12 , and further comprising:
indexing the print signature using the payload information.

15. A system comprising:
a memory for storing computer executable instructions; and
a processing unit for accessing the memory and executing the computer executable instructions, the computer executable instructions comprising:
a preprocessor to generate a filtered signal or a difference signal from a captured image of printed media;
a subdivide area processor to segment the filtered signal or the difference signal in preparation of further image processing of the captured image of printed media;
an area code generator to process segmented output from the subdivide area processor and to recover a print signature from an interior of a halftone that is encoded with payload information; and
a verification system to authenticate the printed media by comparing the recovered print signature with a reference signature stored in a print signature registry, wherein the reference signature includes payload information that is used to index the print signature, wherein the halftone is encoded with one of a unique payload to form a one-to-one mapping between the print signature and the payload information or a common payload to form a many-to-one mapping between the print signature and the payload information.

16. The method of claim 12 , wherein the halftone is encoded with a unique payload to form a one-to-one mapping between the print signature and the payload information.

17. The method of claim 12 , wherein the halftone is encoded with a common payload to form a many-to-one mapping between the print signature and the payload information.

Assignees

• Hewlett Packard Development Co Lp

Inventors

• Ulicheny Robert
• Pollard Stephen
• Gaubatz Matthew
• Simske Steven J

Classifications

• H04N1/405 Primary

  Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels · CPC title

• G06F2218/00

  Aspects of pattern recognition specially adapted for signal processing · CPC title

• H04N1/32144

  embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp · CPC title

• G06K15/1881

  Halftoning (halftoning of still images in general H04N1/405, H04N1/52) · CPC title

• H04N2201/3235

  Checking or certification of the authentication information, e.g. by comparison with data stored independently · CPC title