Steganographic encoding and decoding

• US 8,515,120 B2
• Filed: 02/18/2010
• Issued: 08/20/2013
• 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:
  US12/708,278
• Publication Number:
  US 20100322467A1
• Time in Patent Office: 1,279 Days
• Field of Search: 382/100, 382/162, 382/165, 382/176, 713/176
• US Class Current: 382/100
• 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, in a watermark detector, a method of decoding auxiliary information encoded encoding in an image or video. The method includes: receiving data representing the image or video, wherein the data comprises first data corresponding to a first color channel, second data corresponding to a second color channel and third data corresponding to a third color channel; weighting the first data, the second data and the third data according to at least the following two factors: i) a color direction biased toward an anticipated embedding direction; and ii) anticipated image or video distortion introduced to the first data, second data or third data through scanning or signal processing; and determining from weighted first data, weighted second data and weighted third data, changes in an image or video attribute, in which the auxiliary information is conveyed through the changes to sample values representing the image or video. Of course, other claims and combinations are provided too.

Claims

1. In a watermark detector, a method of decoding auxiliary information encoded in an image or video comprising:

receiving data representing the image or video, wherein the data comprises first data corresponding to a first color channel, second data corresponding to a second color channel and third data corresponding to a third color channel;

weighting the first data, the second data and the third data according to at least the following two factors;

i) a color direction biased toward an anticipated embedding direction; and

ii) anticipated image or video distortion introduced to the first data, second data or third data through scanning or signal processing; and

determining from weighted first data, weighted second data and weighted third data, changes in an image or video attribute, in which the auxiliary information is conveyed through the changes to sample values representing the image or video.

2. The method of claim 1 in which the data is weighted for detection in a blue-yellow direction.

3. The method of claim 1 in which the first data, second data and third data respectively correspond to red, green and blue.

4. The method of claim 1 in which the anticipated image or video distortion is attributable to at least one of compression, signal processing or signal sampling.

5. A non-transitory computer readable medium comprising instructions stored therein, said instructions cause an electronic processor to perform the method of claim 1.

6. A programmed computing device comprising instructions stored in memory to cause said programmed computing device to perform the method of claim 1.

7. An apparatus comprising:

electronic memory for buffering data representing an image or video, in which the data comprises first data corresponding to a first color channel, second data corresponding to a second color channel and third data corresponding to a third color channel;

an electronic processor programmed for;

weighting the first data, the second data and the third data according to at least the following two factors;

i) a color direction biased toward an anticipated embedding direction; and

ii) anticipated image or video distortion introduced to the first data, second data or third data through scanning or signal processing; and

determining from weighted first data, weighted second data and weighted third data, changes in an image or video attribute, in which the auxiliary information is conveyed through the changes to sample values representing the image or video.

8. The apparatus of claim 7 in which the electronic processor is operating to perform at least one of the functions recited therein.