Conditioning imagery to better receive steganographic encoding

• US 20060002583A1
• Filed: 06/01/2005
• Published: 01/05/2006
• Est. Priority Date: 07/02/2004
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M., Bradley, Brett A.
• Granted Patent: US 7,668,334 B2
• Time in Patent Office: Days
• 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

THE present invention relates to steganography and digital watermarking. In one implementation, we provide a method to analyze a digital image to determine whether the digital image will be a suitable host to receive steganographic encoding or digital watermarking. Suitability is determined, at least in part, by analyzing the digital image relative to an expected workflow process through which a watermarked version of the digital image is expected to flow through. Our methods and systems determine whether the digital image forms a suitable host to receive digital watermarking relative to the expected workflow process. If the digital image is not suitable, the digital image is modified to better receive digital watermarking in anticipation of the expected workflow process.

Claims

1. A method to condition an image prior to receiving steganographic encoding, said method comprising:

receiving an image;

evaluating the image relative to an approximation of a workflow process;

based at least on the evaluation, determining whether the image includes characteristics that are conducive to steganographic encoding relative to the expected workflow process, and if not conducive,

modifying the image.

2. The method of claim 1, wherein the approximation of a workflow process comprises an approximation of an expected printing process.

3. The method of claim 2, wherein the approximation of a workflow process further comprises an approximation of an expected scanning process.

4. The method of claim 1, wherein the characteristics comprise at least one of luminance values, tonal values and image variance.

5. The method of claim 4, wherein the characteristics further comprise a percentage of luminance values falling within predetermined ranges.

6. The method of claim 1, wherein the characteristics comprise at least one of relative noise and compression artifacts.

7. The method of claim 1, wherein the steganographic encoding comprises plural-bit digital watermarking.

8. The method of claim 1, further comprising embedding a plural-bit digital watermark in at least one of a modified image and an unmodified image.

9. A method to analyze a digital image to determine whether the digital image will provide a suitable host to receive digital watermarking, said method comprising:

receiving a digital image;

analyzing the digital image to determine where pixel values of the digital image fall within a range corresponding to an expected workflow process;

based on the analysis, determining whether the digital image comprises a suitable host to receive digital watermarking, and, if not suitable,

modifying the digital image to better receive digital watermark in anticipation of the expected workflow process.

10. The method of claim 9, wherein the expected workflow process comprises at least printing.

11. The method of claim 10, wherein the expected workflow process further comprises optical scanning.

12. The method of claim 9, wherein said modifying results in at least one of a luminance change and a tonal change in at least some portions of the digital image.

13. The method of claim 9, wherein said analyzing determines percentages of image pixels that fall within predetermined ranges of criteria.

14. The method of claim 13, wherein the criteria comprises at least one of luminance, color value, tonal value and grayscale value.

15. The method of claim 9, further comprising embedding a plural-bit digital watermark in at least one of a modified version of the digital image and an unmodified version of the digital image.

16. A method to analyze a digital image to determine whether the digital image will be a suitable host to receive steganographic encoding, said method comprising:

analyzing an effect that a workflow process will have on a digital image;

determining whether the effect will result in the digital image, after processing by the workflow process, being less suitable to host steganographic encoding; and

if less suitable, modifying the digital image in anticipation of the workflow process.

17. The method of claim 16, wherein said modifying results in at least one of a luminance change and a tonal change in at least some portions of the digital image.

18. The method of claim 16, wherein said analyzing determines percentages of image pixels that fall within predetermined ranges of criteria.

19. The method of claim 18, wherein the criteria comprises at least one of luminance, color value, tonal value, grayscale value and image variance.

20. The method of claim 16, further comprising embedding plural-bit steganographic encoding in the digital image.