Tile-based digital watermarking techniques

• US 6,879,701 B1
• Filed: 09/29/1999
• Issued: 04/12/2005
• Est. Priority Date: 10/21/1994
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B.
• Primary Examiner(s): Couso, Jose L.
• Application Number:
  US09/408,886
• Time in Patent Office: 2,022 Days
• Field of Search: 382/100, 382/232, 382/284, 355/135, 358/448, 358/454, 358/142, 358/124, 358/450, 380/4, 380/23, 380/25, 380/54, 283/6, 283/93, 283/54, 348/475, 235/494
• US Class Current: 382/100
• CPC Class Codes: B42D 25/00 Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof printing processes to produce identification or security features B41M3/14
• CPC Class Codes: B42D 25/23 Identity cards
• CPC Class Codes: B42D 25/333 Watermarks
• CPC Class Codes: G06F 16/955 using information identifiers, e.g. uniform resource locators [URL]
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 19/06046 Constructional details
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06K 19/18 Constructional details
• CPC Class Codes: G06K 2019/06253 for a specific application
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G06K 7/1447 extracting optical codes from image or text carrying said optical code
• 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: G06Q 20/40145 Biometric identity checks
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06V 30/40 Document-oriented image-based pattern recognition
• CPC Class Codes: G07C 9/253 visually
• CPC Class Codes: G07D 7/0032 using holograms
• CPC Class Codes: G07D 7/0034 : using watermarks
• CPC Class Codes: G07D 7/004 : using digital security elements, e.g. information coded on a magnetic thread or strip
• 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 7/086 : by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/1008 : Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: G07F 7/1016 : Devices or methods for securing the PIN and other transaction-data, e.g. by encryption arrangements for secret communication, see H04L9/00
• CPC Class Codes: G07F 7/12 : Card verification
• CPC Class Codes: G10L 19/018 : Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G11B 20/00086 : Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00094 : involving measures which result in a restriction to authorised record carriers
• CPC Class Codes: G11B 20/00166 : involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
• CPC Class Codes: G11B 20/0021 : involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00884 : involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: G11B 20/00891 : embedded in audio data
• CPC Class Codes: H04B 1/665 : using psychoacoustic properties of the ear, e.g. masking effect
• CPC Class Codes: H04N 1/00005 : relating to image data
• CPC Class Codes: H04N 1/00037 : Detecting, i.e. determining the occurrence of a predetermined state H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00079 : remotely
• CPC Class Codes: H04N 1/32122 : in a separate device, e.g. in a memory or on a display separate from image data
• CPC Class Codes: H04N 1/32144 : embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/3216 : using Fourier transforms
• 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 1/32251 : 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 1/32352 : Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• CPC Class Codes: H04N 19/00 : Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• CPC Class Codes: H04N 19/467 : characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 2005/91321 : the copy protection signal being a copy protection control signal, e.g. a record inhibit signal
• CPC Class Codes: H04N 2005/91335 : the copy protection signal being a watermark
• CPC Class Codes: H04N 21/23892 : involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 : involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 2201/3205 : of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3207 : of an address
• CPC Class Codes: H04N 2201/3225 : of data relating to an image, a page or a document
• CPC Class Codes: H04N 2201/3226 : of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• CPC Class Codes: H04N 2201/3233 : of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 : which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3271 : Printing or stamping
• CPC Class Codes: H04N 2201/3274 : Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 2201/328 : Processing of the additional information
• CPC Class Codes: H04N 5/913 : for scrambling ; for copy protection

Abstract

A tile-based arrangement is employed to effect watermarking of plural-bit auxiliary data into still or moving digital images. In a particular embodiment, the plural-bit auxiliary data is represented as a rectangular block of overlay data. This block is repetitively tiled, both vertically and horizontally, across the image, and combined with the image data to effect the encoding.

Claims

1. In a decoding method that includes receiving a set of data corresponding to an image, and processing same to extract plural-bit auxiliary data hidden therein, an improvement comprising:

identifying uniformly-arrayed rectangular blocks of embedded data across the image, and processing said blocks to extract the auxiliary data therefrom;

wherein each of said rectangular blocks comprises an eight by eight array of sub-elements.

2. The method of claim 1 in which at least certain of said sub-elements has a first bias to encode a “

1”

bit of auxiliary data, a second, opposite bias to encode a “

0”

bit of auxiliary data.

3. The method of claim 1 in which each of said sub-elements comprises a two-by-two array of pixels.

4. In a decoding method that includes receiving a set of data corresponding to an image, and processing same to extract plural-bit auxiliary data hidden therein, an improvement comprising:

identifying uniformly-arrayed rectangular blocks of embedded data across the image, and processing said blocks to extract the auxiliary data therefrom;

wherein each rectangular block encodes all of said plural bits, and the method includes aggregating like data from plural of said blocks.

5. In a method of encoding an image to hide plural-bit auxiliary data therein, an improvement comprising encoding said auxiliary in tiled fashion, both vertically and horizontally, across the image;

wherein each tile comprises an eight by eight array of first sub-blocks.

6. The method of claim 5 in which each first sub-block comprises an eight by eight array of second sub-blocks.

7. The method of claim 6 in which each second sub-block comprises a two by two array of third sub-blocks.

8. The method of claim 7 in which each third sub-block comprises a square grouping of 64 image pixels.

9. In a method of encoding an image to hide plural-bit auxiliary data therein, the image comprising a rectangular array of image elements, an improvement comprising generating a rectangular block of auxiliary data elements, tiling said block repetitively across the image so that each auxiliary data element in each of said blocks corresponds to one of said image elements, and modifying the image elements in accordance with the auxiliary data element corresponding thereto;

including modifying the image elements by relatively greater or lesser amounts depending on local data hiding attributes of the image.

10. In a method of encoding an image to hide plural-bit auxiliary data therein, the image comprising a rectangular array of image elements, an improvement comprising generating a rectangular block of auxiliary data elements, tiling said block repetitively across the image so that each auxiliary data element in each of said blocks corresponds to one of said image elements, and modifying the image elements in accordance with the auxiliary data element corresponding thereto;

wherein the modifying comprises summing.

11. In a decoding method that includes receiving a set of data corresponding to an image, and processing same to extract plural-bit auxiliary data hidden therein, an improvement comprising:

identifying uniformly-arrayed rectangular blocks of embedded data across the image, and processing said blocks to extract the auxiliary data therefrom;

wherein said uniformly-arrayed rectangular blocks are arranged edge-to-edge; and

said blocks each encodes the same information.

12. In a method of encoding an image to hide plural-bit auxiliary data therein, an improvement comprising encoding said auxiliary in tiled fashion, both vertically and horizontally, across the image;

wherein said tiled fashion comprises positioning blocks of data edge to edge; and

said blocks each encodes the same information.