Digital Watermark Systems and Methods

• US 20080130944A1
• Filed: 10/23/2007
• Published: 06/05/2008
• Est. Priority Date: 02/20/1997
• Status: Active Grant

• Current Assignee: Aye M.U. Myint, Digimarc Corporation, Harald Hampel, Manfred Schawaller, Markus J. Schwarz, Norbert Muller, Robert Verkerk
• Original Assignee: Digimarc Corporation
• Inventors: Johnson, Andrew, Biggar, Michael
• Granted Patent: US 8,364,966 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 permutes the content, alters the permuted content to encode a watermark, and inverse-permutes the content to return same to substantially its original form. Related watermark decoding methods are also detailed, as are ancillary features and techniques

Claims

1. A monitoring method, for determining a source of audio data, comprising:

receiving audio data, and storing one or more blocks of same in a buffer;

decoding plural-bit message data encoded as slight changes in the data, said decoding including detecting synchronization information that signals a beginning of the message data;

performing a comparison operation between the decoded plural-bit message data and previously-stored data; and

indicating, based on the foregoing, a source of the audio data.

2. The method of claim 1 wherein the data comprises coefficients in a transform domain.

3. A monitoring method, for determining a source of video data, comprising:

receiving video data, and storing one or more blocks of same in a buffer;

decoding plural-bit message data encoded as slight changes in the data, said decoding including detecting synchronization information that signals a beginning of the message data;

performing a comparison operation between the decoded plural-bit message data and previously-stored data; and

indicating, based on the foregoing, a source of the video data.

4. The method of claim 3 wherein the data comprises coefficients in a transform domain.

5. The method of claim 3 wherein the received data comprises video data that was subjected to MPEG compression after it was encoded with the plural-bit message data, yet the message data is nonetheless decoded therefrom.

6. A method of encoding a sequence of image frames with a complete digital watermark message, comprising:

receiving a sequence of image frames;

segmenting each of plural of said frames into plural blocks;

encoding first and second blocks of a first frame with a first portion of said digital watermark message; and

encoding first and second blocks of a further frame with a different portion of said digital watermark message;

wherein the complete digital watermark message is not encoded in a single frame, but rather is distributed over plural frames of said sequence.

7. A method of processing content data to extract digital watermark data therefrom, the content data comprising plural samples, each sample having a value, the method including the acts:

identifying a group of samples;

determining a mean value of said group of samples;

subtracting said determined mean value from the value of each of said samples in the group, to yield a set of mean-removed sample values; and

extracting digital watermark data based on said set of mean-removed sample values.

8. The method of claim 7 that further includes generating transform data by transforming said set of mean-removed sample values to a different domain, and extracting the digital watermark data from said transform data.

9. The method of claim 7 wherein said content data comprises audio content.

10. The method of claim 7 wherein said content data comprises visual content.

11. A method of watermark processing comprising:

receiving a set of content data; and

processing same to either embed a watermark therein, or extract a watermark therefrom, in accordance with an algorithm;

wherein the method includes changing a keying parameter of said algorithm during processing of said content data.

12. A method of watermark processing that includes the acts:

receiving content data representing audio, image or video information;

permuting at least some of the content data to scramble same;

altering the content data following said permuting to represent watermark data therein; and

inverse-permuting the content data following said altering.

13. The method of claim 12 that further includes transforming the content data to a different domain prior to said altering, and inverse-transforming the content data back to an original domain after said altering.

14. The method of claim 12 that further includes transforming the content data to a different domain between said permuting and altering acts, and inverse-transforming the content data between said altering and inverse-permuting acts.

15. A method of watermark processing that includes the acts:

receiving content data representing audio, image or video information;

permuting at least some of the content data; and

decoding watermark data from the content data following said permuting.

16. The method of claim 15 that further includes inverse-permuting the content data following said decoding.

17. The method of claim 15 that further includes transforming the content data to a different domain prior to said decoding.

18. The method of claim 15 that further includes transforming the content data to a different domain between said permuting and decoding acts.