Image marking with error correction

• US 6,317,505 B1
• Filed: 11/03/1999
• Issued: 11/13/2001
• Est. Priority Date: 07/31/1992
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Powell, Robert D., Nitzberg, Mark J.
• Primary Examiner(s): Johns, Andrew W.
• Application Number:
  US09/432,532
• Time in Patent Office: 741 Days
• Field of Search: 382/100, 382/112, 382/232, 340/825.34, 340/5.8, 340/5.86, 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

A method of marking a work of authorship without apparent evidence of data alteration. The work (e.g., an image) is represented by a set of data elements (e.g., pixels). The marking includes providing first plural-bit data, and computing therefrom additional, error correcting data. This composite set of data is used in image marking, permitting at least certain errors to be discerned and corrected when the marking is later discerned from the image.

Claims

1. A method of marking a work of authorship without apparent evidence of data alteration, the work being represented by a set of data elements, the method comprising:

providing first plural-bit data;

computing from the first plural-bit data additional, error correcting data corresponding thereto; and

altering the values of at least certain of said data elements in accordance with composite data comprising the first data and the error correcting data, including increasing the value of a first data element, decreasing the value of a second data element, 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.

2. A method of marking a work of authorship without apparent evidence of data alteration, the work being represented by a set of data elements, the method comprising providing first plural-bit data, computing from the first plural-bit data additional, error correcting data corresponding thereto;

and altering the values of at least certain of said data elements in accordance with composite data comprising the first data and the error correcting data, including altering said certain data elements by an amount based, at least in part, on initial values thereof.

3. The method of claim 2 in which said amount is ten percent or less.

4. A method of marking a work of authorship without apparent evidence of data alteration, the work being represented by a set of data elements, the method comprising providing first plural-bit data, computing from the first plural-bit data additional, error correcting data corresponding thereto;

and altering the values of at least certain of said data elements in accordance with composite data comprising the first data and the error correcting data;

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