Digital watermark systems and methods

• US 8,037,311 B2
• Filed: 04/02/2007
• Issued: 10/11/2011
• Est. Priority Date: 02/20/1997
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Johnson, Andrew, Biggar, Michael
• Primary Examiner(s): Moazzami; Nasser
• Assistant Examiner(s): Louie; Oscar
• Application Number:
  US11/695,523
• Publication Number:
  US 20070230739A1
• Time in Patent Office: 1,653 Days
• Field of Search: 713/176, 462/903, 399/366
• US Class Current: 713/176
• 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 2201/0051 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: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0083 whereby only watermarked image required at decoder, e.g. source-based, blind, oblivious
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/3216 using Fourier transforms
• CPC Class Codes: H04N 1/32165 using cosine transforms
• CPC Class Codes: H04N 1/32176 using Walsh, Hadamard or Walsh-Hadamard transforms
• CPC Class Codes: H04N 1/32187 with selective or adaptive application of the additional information, e.g. in selected frequency coefficients
• CPC Class Codes: H04N 19/00 Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• 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 2201/3233 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

A digital watermark is added to audio or visual content. An illustrative embodiment segments the content, permutes the segments, and transforms such data into another domain. The transformed data is altered slightly to encode a watermark. The altered data can then be inverse-transformed, and inverse-permuted, to return same to substantially its original form. Related watermark decoding methods are also detailed, as are ancillary features and techniques.

Claims

1. A method comprising:

altering, with a computing device, a sign of at least one coefficient associated with data corresponding to audio, image, or video content in accordance with data corresponding to a digital watermark; and

prior to the altering, processing, with the computing device, the content data with a pseudo-random permutation function.

2. The method of claim 1, wherein the data corresponding to the content has a flatter power spectral density following the processing.

3. The method of claim 1, further comprising transforming the data corresponding to the content to an orthogonal domain before the altering.

4. The method of claim 3, wherein the transforming comprises transforming with a discrete cosine transform.

5. The method of claim 1, wherein the altering comprises modifying a sign of at least a portion of the data corresponding to the content.

6. The method of claim 1, wherein the permuted data comprises a sequence of data, and further comprising selecting certain data in the sequence for alteration based on a keyed function.

7. The method of claim 1, wherein the processing of the data corresponding to the content with the pseudo-random permutation function is performed by computer circuitry of the computing device.

8. The method of claim 1, wherein the pseudo-random permutation function comprises a spectral whitening operation.

9. A method comprising:

analyzing, with a computing device, a sign of at least one coefficient associated with content data corresponding to audio, image, or video content to discern whether digital watermark data is encoded therein; and

prior to performing the analyzing, applying, with the computing device, a pseudo-random permutation function to the content data to yield permuted content data.

10. The method of claim 9, wherein the permuted content data has a flatter power spectral density than the content data.

11. The method of claim 9, wherein the analyzing comprises discerning a sign of at least a portion of the content data.

12. The method of claim 9, wherein the analyzing proceeds without reference to an unencoded original of the content data.

13. The method of claim 9, wherein applying the pseudo-random permutation function to the content data is performed by computer circuitry of the computing device.

14. A method comprising:

receiving, with a computing device, data that corresponds to desired audio or visual information;

scrambling, using the computing device, the data using a predetermined random permutation, so that the data no longer corresponds to the desired audio or visual information; and

performing a watermarking process on the scrambled data by altering a sign of at least one coefficient of the scrambled data.

15. The method of claim 14, further comprising performing an inverse-scrambling operation on the scrambled data following performance of the watermarking process.

16. The method of claim 14, wherein the received data corresponds to audio information.

17. The method of claim 14, wherein the received data corresponds to image information.

18. The method of claim 17, wherein the received data corresponds to video information.

19. The method of claim 14, wherein the scrambling or performing the watermarking process is performed by computer circuitry of the computing device.

20. The method of claim 14, wherein the pseudo-random permutation function comprises a spectral whitening operation.

21. The method of claim 14, wherein performing the watermarking process on the scrambled data comprises inserting a watermark in areas corresponding to low spatial frequencies.

22. An apparatus comprising:

a scrambler having an input to which content data is applied, and an output to which scrambled content data is provided using a predetermined random permutation; and

a processor configured to perform a watermarking operation on the scrambled content data by altering a sign of at least one coefficient of the scrambled data.

23. A system comprising:

a memory configured to store audio, image, or video content; and

;

a processor operatively coupled to the memory and configured to;

alter a sign of at least one coefficient associated with data corresponding to the content in accordance with data corresponding to a digital watermark that represents a message; and

prior to the alteration, process the data corresponding to the content with a pseudo-random permutation function.

24. A system comprising:

an input for receiving data that corresponds to desired audio or visual information;

means for scrambling the data using a predetermined random permutation so that the data no longer corresponds to the desired audio or visual information; and

means for performing a watermarking process on the scrambled data by altering a sign of at least one coefficient of the scrambled data.

25. A system comprising:

a memory configured to store data corresponding to audio, image or video content; and

a processor operatively coupled to the memory and configured to;

analyze a sign of at least one coefficient associated with the data corresponding to the content to discern whether digital watermark data is encoded therein; and

prior to the analysis, apply a pseudo-random permutation function to the content data to yield permuted content data.

26. A system comprising:

means for analyzing a sign of at least one coefficient associated with content data corresponding to audio, image, or video content to discern whether digital watermark data is encoded therein; and

means for—

prior to the analysis—

applying a pseudo-random permutation function to the content data to yield permuted content data.