Wavelet domain watermarks

• US 8,194,915 B2
• Filed: 01/15/2008
• Issued: 06/05/2012
• Est. Priority Date: 02/14/2000
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Sharma, Ravi K., Alattar, Adnan M., Ahmed, Farid, Rhoads, Geoffrey B.
• Primary Examiner(s): Bali, Vikkram
• Application Number:
  US12/014,690
• Publication Number:
  US 20080292134A1
• Time in Patent Office: 1,603 Days
• Field of Search: 382/100, 713/176
• 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
• CPC Class Codes: H04H 20/31 using in-band signals, e.g. subsonic or cue signal
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/3217 using wavelet transforms
• CPC Class Codes: H04N 1/32192 according to calculated or estimated visibility of the additional information in the image
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32288 Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
• CPC Class Codes: H04N 1/32352 Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 19/645 by grouping of coefficients into blocks after the transform
• 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 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/4627 Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• 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
• CPC Class Codes: H04N 2201/3281 Encryption; Ciphering
• CPC Class Codes: H04N 2201/3284 for error correction
• CPC Class Codes: H04N 7/163 by receiver means only

Abstract

A wavelet domain watermark encoder and decoder embed and detect auxiliary signals in a media signal, such as a still image, video or audio signal. The watermark encoders and decoders employ techniques that take advantage of processing plural levels of resolution of the signal to embed and detect auxiliary information in the media signal.

Claims

1. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary information is substantially imperceptible in an output form of the media signal;

the method comprising;

receiving a wavelet decomposition of the media signal having two or more levels of resolution;

performing detection at each of plural levels of resolution in the wavelet decomposition to produce detection results corresponding to the plural levels of resolution; and

combining the detection results to determine the auxiliary information, including weighting the detection results from the plural levels based on an analysis performed on the plural different bands.

2. The method of claim 1 wherein performing detection includes performing a correlation detection.

4. The method of claim 1 wherein the plural levels include an approximate level.

5. The method of claim 1 including performing a log sampling of at least one of the plural levels of resolution prior to performing the detection on the log sampling.

6. The method of claim 1 including performing a polar sampling of at least one of the plural levels of resolution prior to performing the detection on the polar sampling.

7. The method of claim 1 wherein the wavelet decomposition comprises a translation invariant wavelet decomposition.

8. A non-transitory computer readable medium on which is stored instructions, which when executed by a computer, perform the method of claim 1.

3. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary information is substantially imperceptible in an output form of the media signal;

the method comprising;

receiving a wavelet decomposition of the media signal having two or more levels of resolution;

performing detection at each of plural levels of resolution in the wavelet decomposition to produce detection results corresponding to the plural levels of resolution; and

combining the detection results to determine the auxiliary information;

wherein performing detection includes performing a correlation detection; and

wherein combining includes computing a weighted combination of the detection results in which the detection results are weighted based on a measure of reliability of auxiliary information detected at the plural levels.

9. A method of encoding an auxiliary signal in a media signal comprising:

receiving a wavelet decomposition of the media signal having two or more levels of resolution;

adaptively selecting subbands for insertion of the auxiliary signal; and

applying an embedding function to modify coefficients in the selected subbands according to elements of the auxiliary signal to encode the auxiliary signal such that the auxiliary signal is substantially imperceptible in an output form of the media signal.

10. The method of claim 9 wherein the embedding function adjusts wavelet coefficients so that the coefficients conform to a function representing embedded auxiliary data.

11. The method of claim 9 wherein the wavelet decomposition comprises a translation invariant wavelet decomposition.

12. A non-transitory computer readable medium on which is stored instructions, which when executed by a computer, perform the method of claim 9.

13. A method of encoding an auxiliary signal in a media signal comprising:

performing a translation invariant wavelet decomposition of the media signal into two or more levels of resolution;

selecting subbands for insertion of the auxiliary signal; and

applying an embedding function to modify coefficients in the selected subbands according to elements of the auxiliary signal to encode the auxiliary signal such that the auxiliary signal is substantially imperceptible in an output form of the media signal.

14. The method of claim 13 wherein the decomposition includes an approximate level and one or more levels of detail, and including embedding a synchronization signal in the approximate level.

15. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary information is substantially imperceptible in an output form of the media signal;

the method comprising;

receiving a wavelet decomposition of the media signal having two or more levels of resolution;

performing a log sampling of each of plural levels of resolution in the wavelet decomposition; and

performing detection on the log sampling to produce detection results corresponding to the plural levels of resolution.

16. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary information is substantially imperceptible in an output form of the media signal;

the method comprising;

receiving a wavelet decomposition of the media signal having two or more levels of resolution;

performing a polar sampling of each of plural levels of resolution in the wavelet decomposition; and

performing detection on the polar sampling to produce detection results corresponding to the plural levels of resolution.