DIGITAL WATERMARK SYSTEMS AND METHODS

• US 20070230739A1
• Filed: 04/02/2007
• Published: 10/04/2007
• Est. Priority Date: 02/20/1997
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Johnson, Andrew, Biggar, Michael
• Granted Patent: US 8,037,311 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 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. In a method of encoding audio, image or video content with a digital watermark that is substantially imperceptible to humans, the method including altering data corresponding to said content in accordance with data corresponding to said watermark, an improvement that includes—

prior to said altering—

processing said content data with a pseudo-random permutation function.

2. The method of claim 1 wherein said data has a substantially flat power spectral density following said processing.

3. The method of claim 1 that further includes transforming the content data to an orthogonal domain before said altering.

4. The method of claim 3 wherein said transforming includes transforming with a discrete cosine transform.

5. The method of claim 1 wherein said altering comprises modifying a sign of one or more data corresponding to said content.

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

8. The method of claim 1, wherein said permuted content data has a substantially flat power spectral density.

7. In a method of processing data corresponding to audio, image or video content, the method including analyzing said content data to discern digital watermark data encoded therein, an improvement that includes—

prior to performing said analyzing—

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

9. The method of claim 7 wherein said analyzing includes discerning a sign of one or more data corresponding to said content.

10. The method of claim 7, wherein the decoding proceeds without reference to an unencoded original of said content data.

11. A method that includes:

receiving data that corresponds to desired audio or visual information;

scrambling said data, so that it no longer corresponds to said desired audio or visual information; and

performing a watermarking process on said scrambled data.

12. The method of claim 11 that further includes performing an inverse-scrambling operation on said scrambled data following performance of said watermarking process.

13. The method of claim 11 wherein said received data corresponds to audio information.

14. The method of claim 11 wherein said received data corresponds to image information.

15. The method of claim 14 wherein said received data corresponds to video information.

16. An apparatus including:

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

a processor for performing a watermarking operation on said scrambled content data.