Decoding hidden data from imagery

• US 7,068,812 B2
• Filed: 03/07/2005
• Issued: 06/27/2006
• Est. Priority Date: 07/31/1992
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Nitzberg, Mark, Powell, Robert D.
• Primary Examiner(s): Johns, Andrew W.
• Application Number:
  US11/074,997
• Publication Number:
  US 20050147276A1
• Time in Patent Office: 477 Days
• Field of Search: 382/100, 382/232, 380/210, 380/252, 380/287, 380/54, 713/176, 370/527, 370/529
• US Class Current: 382/100
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0081 whereby both original and watermarked images are required at decoder, e.g. destination-based, non-blind, non-oblivious
• CPC Class Codes: G07D 7/0047 using checkcodes, e.g. coded numbers derived from serial number and denomination
• CPC Class Codes: G07D 7/0056 involving markings of altered colours
• CPC Class Codes: G07D 7/12 Visible light, infrared or ultraviolet radiation
• CPC Class Codes: G07D 7/2008 using pre-processing, e.g. de-blurring, averaging, normalisation or rotation
• CPC Class Codes: G07D 7/2033 Matching unique patterns, i.e. patterns that are unique to each individual paper
• CPC Class Codes: G07F 7/08 by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/12 Card verification
• 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 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 1/32245 Random or pseudorandom selection of pixels
• CPC Class Codes: H04N 1/32251 in multilevel data, e.g. greyscale or continuous tone data
• CPC Class Codes: H04N 1/32288 Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
• CPC Class Codes: H04N 1/3232 Robust embedding or watermarking
• 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 2201/327 : which are undetectable to the naked eye, e.g. embedded codes

Abstract

A digital image in which hidden information has been encoded, is processed to discern the hidden information. This processing can include identifying geometric distortions of the image (e.g., cropping, scaling, rotation), and compensating for such identified distortions.

Claims

1. A method of processing image data to recover hidden information, comprising:

discerning, from said image data, a message hidden therein, said discerning including performing an algorithmic registration process to resolve an initially unknown variable needed to discern the message from the image data, said image data corresponding to an encoded image corrupted by a geometrical transformation process, wherein the message is discerned notwithstanding said geometrical image transformation.

2. The method of claim 1 in which said discerning includes:

analyzing said image data to determine at least one geometrical transformation parameter; and

employing said transformation parameter in discerning from said image data the message hidden therein.

3. The method of claim 2 wherein said unknown variable comprises said geometrical transformation parameter.

4. The method of claim 2 which includes employing said transformation parameter to compensate the image data for said transformation, and discerning the message from compensated image data.

5. The method of claim 2 in which said transformation parameter comprises a scale factor.

6. The method of claim 2 in which said transformation parameter comprises a rotation factor.

7. The method of claim 1 in which said geometrical transformation process comprises scaling.

8. The method of claim 1 in which said geometrical transformation process comprises rotation.

9. The method of claim 1 in which said geometrical transformation process comprises cropping.

10. The method of claim 1 in which the encoded image is produced by a message encoding process in which the relative strength of the encoded message changes locally in accordance with local characteristics of the image.

11. The method of claim 1 in which said discerning is performed using a representation of said image in the spatial image domain, rather than in a transformed domain.

12. The method of claim 1 in which the message comprises an N-bit signal.

13. The method of claim 12 in which N is greater than or equal to two.

14. The method of claim 1 in which the message is represented by a pattern that was summed with said image.

15. The method of claim 1 in which the image data comprises motion picture data.

16. The method of claim 1 in which the message was encoded as a pattern, and said pattern was determined, in part, as a function of the image in which it was to be encoded.

17. The method of claim 1 that includes:

rendering said image on a surface;

sensing said image from the surface; and

recovering the hidden information notwithstanding losses associated with said rendering/sensing of said image.

18. A computer storage medium having stored thereon instructions for causing a programmable device to perform the method of claim 1.

19. A method of processing image data to recover digital data hidden therein, comprising:

geometrically transforming said image data to correspond to reference image data;

determining a difference pattern between the geometrically-transformed image data and said reference image data; and

processing the difference pattern to decode digital data encoded therein.

20. The method of claim 19, wherein said image data comprises motion picture data.