Steganographic encoding and decoding

• US 9,282,216 B2
• Filed: 06/03/2014
• Issued: 03/08/2016
• Est. Priority Date: 07/02/2004
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M., Sharma, Ravi K., Rodriguez, Tony F.
• Primary Examiner(s): Johns, Andrew W
• Application Number:
  US14/294,845
• Publication Number:
  US 20150071484A1
• Time in Patent Office: 644 Days
• Field of Search: 382/100, 382/162, 382/232, 713/176, 358/3.28
• US Class Current: 1/1
• 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 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77
• CPC Class Codes: G06T 2201/0083 whereby only watermarked image required at decoder, e.g. source-based, blind, oblivious
• 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 1/32267 combined with processing of the image
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 1/6005 with luminance or chrominance signals, e.g. LC1C2, HSL or YUV
• CPC Class Codes: H04N 1/6008 with primary colour signals, e.g. RGB or CMY(K)
• CPC Class Codes: H04N 2201/3228 further additional information (metadata) being comprised in the identification information
• 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

Abstract

This patent document relates generally to steganography and digital watermarking. One claim recites, a method of encoding auxiliary information in an image or video. The method includes: determining a watermark tweak for an attribute of an image or video sample to encode auxiliary information in the image or video; and altering color values of the image or video sample to effect the watermark tweak, said altering alters color values based at least in part on both: i) visibility of color value alterations, and ii) anticipated watermark detection. Of course, other claims are provided too.

Claims

1. A method of encoding auxiliary information in an image or video comprising:

determining a watermark tweak for an attribute of an image or video sample to encode auxiliary information in the image or video; and

altering color values of the image or video sample to effect the watermark tweak, said altering alters color values based at least in part on both;

i) visibility of color value alterations, and

ii) anticipated watermark detection.

2. The method of claim 1 in which the anticipated watermark detection comprises a metric representing distortion attributable to an optical sensor.

3. The method of claim 2 in which the distortion comprises at least one of compression, noise or signal sampling.

4. The method of claim 1 in which the alterations are in the blue-yellow direction.

5. The method of claim 1 in which the alterations affect each of at least a cyan color channel, a magenta color channel and a yellow color channel, with watermark tweaks being embedding with different embedding significance in at least two of the color channels.

6. The method of claim 1 in which the alterations are made to reduce watermark visibility.

7. The method of claim 1 in which the watermark tweak comprises a change in luminance, and the alterations are made to have an equivalent change in luminance while being weighted differently among a plurality of color channels.

8. The method of claim 1 in which the watermark tweak comprises a change in chrominance, and the alterations made to have an equivalent change in chrominance while being weighted differently among a plurality of color channels.

9. A non-transitory computer readable medium having instructions stored thereon to cause an electronic processor to perform the method of claim 1.

10. The method of claim 1 further comprising:

determining a plurality of watermark tweaks corresponding attributes of image or video samples to encode auxiliary information in the image or video; and

altering color values of the image or video samples to effect the watermark tweaks, said altering alters color values based at least in part on both;

i) visibility of color value alterations, and ii) anticipated watermark detection.

11. An apparatus comprising:

electronic memory for buffering samples corresponding to an image or video;

an electronic processor programmed for;

determining changes for attributes of an image or video sample to encode watermark information in the image or video; and

altering color values of the image or video samples to effect the changes, said altering alters color values based at least in part on both;

i) visibility of color value alterations, and ii) anticipated watermark detection.

12. The apparatus of claim 11 in which the anticipated watermark detection comprises a metric representing distortion attributable to an optical sensor.

13. The apparatus of claim 12 in which the distortion comprises at least one of compression, noise or signal sampling.

14. The apparatus of claim 11 in which the changes comprise a change in luminance, and the alterations are made to have an equivalent change in luminance while being weighted differently among a plurality of color channels.

15. The apparatus of claim 11 in which the alterations are in the blue-yellow direction.

16. The apparatus of claim 11 in which the alterations affect each of at least a cyan color channel, a magenta color channel and a yellow color channel, with watermark information being embedding with different embedding significance in at least two of the color channels.

17. The apparatus of claim 11 in which the alterations are made to reduce watermark visibility.

18. The apparatus of claim 11 in which the changes comprise a change in chrominance, and the alterations are made to have an equivalent change in chrominance while being weighted differently among a plurality of color channels.

19. The apparatus of claim 11 in which the electronic processor is programmed for determining a plurality of watermark tweaks comprising the changes for corresponding attributes of an image or video samples to encode auxiliary information in the image or video;

and altering color values of the image or video samples to effect the watermark tweaks, the altering alters color values based at least in part on both;

i) visibility of color value alterations, and ii) anticipated watermark detection.

20. An apparatus comprising:

an input to receive samples corresponding to a digital image or video;

electronic memory for buffering the samples corresponding to an image or video;

means for determining changes for attributes of an image or video sample to encode watermark information in the image or video; and

means for altering color values of the image or video samples to effect the changes, said altering alters color values based at least in part on both;

i) visibility of color value alterations, and ii) anticipated watermark detection.