Color adaptive watermarking

• US 7,391,880 B2
• Filed: 07/03/2003
• Issued: 06/24/2008
• Est. Priority Date: 02/14/2000
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M., Rhoads, Geoffrey B.
• Primary Examiner(s): Desire; Gregory M
• Application Number:
  US10/613,913
• Publication Number:
  US 20040125983A1
• Time in Patent Office: 1,818 Days
• Field of Search: 358/529, 358/534, 358/535, 358/548, 358/549, 358/1.9, 358/500, 358/504, 358/519, 358/520, 382/100, 382/162, 382/163, 382/165, 382/232, 382/253, 382/276, 382/279, 382/284, 382/248, 382/280, 382/167, 235/468, 235/469, 235/494, 235/462, 235/465, 347/131, 347/240, 347/247, 347/251, 348/460, 348/584, 380/205, 380/210, 380/213
• US Class Current: 382/100
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06T 1/0021 Image watermarking
• 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 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: H04H 20/31 using in-band signals, e.g. subsonic or cue signal
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• 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 1/32251 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 1/32293 Repeating the additional information in a regular pattern
• CPC Class Codes: H04N 1/32309 in colour image data
• 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 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 19/645 by grouping of coefficients into blocks after the transform
• 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 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/4627 : Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• 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 2201/3233 : 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 2201/3284 : for error correction
• CPC Class Codes: H04N 7/163 : by receiver means only

Abstract

The presently claimed invention relates generally to data encoding and steganography. One combination recites a method of encoding data representing color imagery with an auxiliary signal. The method includes: providing a set of encoding values for a data sample; determining a color characteristic associated the data sample based on associated color values; and selectively scaling color values in the data sample based on the color characteristic to encode at least a portion of the auxiliary signal in the data representing color imagery. Of course, other combinations are provided as well.

Claims

1. A method to encode an image with a digital watermark, wherein the image comprises a plurality of color channels, said method comprising:

determining a color characteristic for a group of image samples;

based at least in part on the characteristic, determining for the group of image samples which of the plurality of color channels should receiving encoding;

transforming from the group of image samples at least one determined color channel that should receive encoding into a transform domain; and

altering transform domain coefficients of the at least one determined color channel to encode the digital watermark.

2. The method of claim 1, further comprising transforming an altered color channel into a spatial domain.

3. The method of claim 1, where the characteristic identifies which of the color channels will best hide the digital watermark in terms of visibility.

4. A method of encoding a color image with an auxiliary signal, wherein the auxiliary signal comprises encoding values, and wherein the color image comprises an array of color values, said method comprising:

providing a set of encoding values for an image sample;

determining a color characteristic for the image sample based on its color values; and

selectively scaling color values in the image sample based on the color characteristic to encode at least a portion of the auxiliary signal in the color image in accordance with at least the encoding values.

5. The method of claim 4, wherein the scaling effects a change in luminance.

6. The method of claim 5, wherein the scaling comprises a scale to black.

7. The method of claim 5, wherein the scaling comprises a scale to white.

8. The method of claim 4, wherein the color characteristic comprises yellow content.

9. A method to encode data representing imagery with a digital watermark, wherein the data represents a plurality of colors, said method comprising:

determining a color characteristic for a group of data samples;

based at least in part on the characteristic, determining for the group of data samples which of the plurality of colors should receiving encoding;

transforming from the group of data samples data representing at least one determined color that should receive encoding into a transform domain; and

altering transform domain coefficients of the data representing at least one determined color to encode the digital watermark.

10. The method of claim 9 further comprising transforming data representing an altered color into a spatial domain.

11. The method of claim 9 where the characteristic identifies which of the colors will best hide the digital watermark in terms of visibility.

12. The method of claim 9 wherein the imagery comprises a digital image or video.

13. A method of encoding data representing color imagery with an auxiliary signal, said method comprising:

providing a set of encoding values for a data sample;

determining a color characteristic associated the data sample based on associated color values; and

selectively scaling color values in the data sample based on the color characteristic to encode at least a portion of the auxiliary signal in the data representing color imagery.

14. The method of claim 13 wherein the selectively scaling effects a change in luminance.

15. The method of claim 14 wherein the selectively scaling comprises a scale to black.

16. The method of claim 14 wherein the selectively scaling comprises a scale to white.

17. The method of claim 13, wherein the color characteristic are associated with yellow content.

18. The method of claim 13 wherein the color imagery comprises a digital color image or video.

19. The method of claim 18 wherein the auxiliary data is steganographically encoded in the data representing color imagery.