Data hiding based on neighborhood attributes

• US 6,137,892 A
• Filed: 11/03/1999
• Issued: 10/24/2000
• Est. Priority Date: 07/31/1992
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Powell, Robert D., Nitzberg, Mark J.
• Primary Examiner(s): Johns, Andrew W.
• Application Number:
  US09/432,541
• Time in Patent Office: 356 Days
• Field of Search: 382/100, 382/112, 382/232, 340/825.34, 356/71, 902/1, 902/4, 902/6, 283/17, 283/72, 283/73, 283/113, 283/901, 380/210, 380/287, 380/54
• 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

Plural-bit data is encoded in an image without leaving apparent evidence of image alteration. The image is represented by data elements (e.g., pixels) whose values are changed to effect the encoding. The particular data elements to be changed are selected not on their individual values, but rather on an attribute of a neighboring group of data elements.

Claims

1. A method of marking a work of authorship to encode a plural-bit code therein, the work being represented as a set of plural data elements, the method including selecting data elements to be changed to effect said marking based not just on the values of individual data elements, but on an attribute of a neighborhood of data elements, said neighborhood being comprised of data elements having substantially non-uniform values.

2. The method of claim 1 in which said attribute is a local extrema in values of said individual elements.

3. The method of claim 1 in which the work comprises an image.

4. The method of claim 3 in which the image comprises pixels.

5. The method of claim 1 that includes increasing the value of a first data element, and decreasing the value of a second data element.

6. The method of claim 5 that includes increasing the values of other data elements adjoining the first data element, and reducing the values of other data elements adjoining the second data element.

7. The method of claim 1 that includes changing said selected data elements based, at least in part, on initial values thereof.

8. The method of claim 1 that includes changing the values of the selected data elements by ten percent or less.

9. The method of claim 1 wherein at least certain excerpts of the work are not marked because marking in such excerpts would more likely be conspicuous.

10. The method of claim 1 wherein each changed element corresponds to a single bit, only, of the plural-bit code.

11. The method of claim 10 wherein plural changed elements each correspond to a single bit of the plural-bit code.