Encoding and decoding signals for digital watermarking

• US 7,489,801 B2
• Filed: 05/16/2006
• Issued: 02/10/2009
• Est. Priority Date: 04/25/2001
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Stach, John, Sharma, Ravi K.
• Primary Examiner(s): Azarian; Seyed
• Application Number:
  US11/383,742
• Publication Number:
  US 20070110272A1
• Time in Patent Office: 1,001 Days
• Field of Search: 382/100, 382/112, 382/162, 382/182, 382169-172, 382232-235, 382/237, 382/242, 382/250, 382/251, 382/191, 382/260, 382/248, 382/294, 382/274, 382/276, 382/305, 235/468, 713/176, 380/203, 380/210, 348/475, 360/77.08, 375/240.25
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain

Abstract

This disclosure describes methods and systems for encoding a digital watermark into and/or detecting a digital watermark from a host (or media) signal such as audio, video or imagery. One implementation involves a method of detecting a digital watermark. The method includes: receiving a host signal carrying a digital watermark; computing attributes of the host signal; using the attributes of the host signal to compute a key; and using the key to detect the digital watermark in a transform domain dependent on the key. Other methods, systems and apparatus are provided as well.

Claims

1. A method comprising:

obtaining a media signal;

computing a reduced-bit representation of the media signal;

influencing a digital watermark embedding process with the reduced-bit representation of the media signal; and

embedding a digital watermark in the media signal with the influenced digital watermark embedding process, wherein said act of embedding embeds at least a reference signal in the media signal that is used to correct or compensate for geometric distortion, wherein the reduced-bit number seeds a pseudorandom number generator used to generate the reference signal.

2. A method comprising:

obtaining a media signal;

computing a reduced-bit representation of the media signal;

influencing a digital watermark embedding process with the reduced-bit representation of the media signal; and

embedding a digital watermark in the media signal with the influenced digital watermark embedding process, wherein the watermark embedding process embeds at least one digital watermark component in a transform domain that is dependent on the reduced-bit representation.

3. A method comprising:

obtaining a media signal;

computing a reduced-bit representation of the media signal;

influencing a digital watermark embedding process with the reduced-bit representation of the media signal; and

embedding a digital watermark in the media signal with the influenced digital watermark embedding process, wherein the reduced-bit representation is used to generate a watermark embedding key associated with a transform domain.

4. A method comprising:

receiving a media signal comprising a digital watermark hidden therein;

computing a reduced-bit representation of the media signal;

influencing detection of a digital watermark detector with the reduced-bit representation of the media signal; and

analyzing the media signal to detect the digital watermark hidden therein with the influenced digital watermark detector, wherein the digital watermark comprises at least one component that is detectable in a transform domain, and wherein the transform domain is associated with the reduced-bit representation.

5. A method comprising:

receiving a media signal comprising a digital watermark hidden therein;

computing a reduced-bit representation of the media signal;

influencing detection of a digital watermark detector with the reduced-bit representation of the media signal; and

analyzing the media signal to detect the digital watermark hidden therein with the influenced digital watermark detector, wherein the reduced-bit representation is used to calculate a detection key used by the digital watermark detector to detect the digital watermark.

6. A method comprising:

receiving a media signal comprising a digital watermark hidden therein;

computing a reduced-bit representation of the media signal;

influencing detection of a digital watermark detector with the reduced-bit representation of the media signal; and

analyzing the media signal to detect the digital watermark hidden therein with the influenced digital watermark detector, wherein the reduced-bit representation seeds a pseudorandom number generator used at least in part in detecting the digital watermark.

7. A method comprising:

receiving a media signal comprising a digital watermark hidden therein;

computing a reduced-bit representation of the media signal;

influencing detection of a digital watermark detector with the reduced-bit representation of the media signal; and

analyzing the media signal to detect the digital watermark hidden therein with the influenced digital watermark detector, wherein the act of influencing detection of a digital watermark detector with the reduced-bit representation of the media signal comprises at least an act of utilizing a transform domain that is associated with the reduced-bit representation of the media signal.

8. A method of detecting a digital watermark comprising:

receiving a host signal carrying a digital watermark;

computing attributes of the host signal;

using the attributes of the host signal to compute a key; and

using the key to detect the digital watermark in a transform domain dependent on the key.

9. The method of claim 8 wherein the host signal comprises at least one of audio, video or imagery.

10. The method of claim 8 wherein the digital watermark comprises at least a reference signal that is used to correct or compensate for geometric distortion.

11. The method of claim 8 wherein the attributes seed a pseudo-random number generator used to compute the key.

12. A method comprising:

obtaining an audio or video signal;

computing a value from the audio or video signal;

influencing a digital watermark embedding process with the value from the audio or video signal, where the value influences magnitudes of at least some coefficients associated with the audio or video signal in a transform domain; and

embedding a digital watermark in the audio or video signal with the influenced digital watermark embedding process.

13. The method of claim 12 where the value comprises a hash.

14. The method of claim 12 where the value influences a phase of at least some coefficients associated with the audio or video signal in a transform domain.

15. A method comprising:

receiving an audio or video signal comprising a digital watermark hidden therein;

computing a value of the audio or video signal;

influencing detection of a digital watermark detector with the value where the value specifies magnitudes of at least some coefficients associated with the digital watermark; and

analyzing the audio or video signal to detect the digital watermark hidden therein with the influenced digital watermark detector.

16. The method of claim 15 where the value comprises a hash.