Wavelet domain watermarks

• US 7,319,775 B2
• Filed: 07/12/2001
• Issued: 01/15/2008
• Est. Priority Date: 02/14/2000
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Ahmed, Farid, Sharma, Ravi K., Rhoads, Geoffrey B., Alattar, Adnan M.
• Primary Examiner(s): Johns; Andrew W.
• Assistant Examiner(s): Mackowey; Anthony
• Application Number:
  US10/333,344
• Publication Number:
  US 20040105569A1
• Time in Patent Office: 2,378 Days
• Field of Search: 382/100, 382/232, 382294-298, 380/252, 380/287, 713/176, 370/527, 370/529
• 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. A watermark orientation signal is embedded in a wavelet decomposed signal to facilitate detection of the watermark in a geometrically distorted version of the embedded signal. In some configurations, the watermark signal forms a pattern in a transform domain used to perform synchronization of the watermark. The pattern has attributes used to determine orientation of the watermark in a geometrically distorted version of the media signal. The attributes carry two or more auxiliary message symbols in the watermark, and the attributes both carry the two or more auxiliary message symbols and form the pattern used to perform synchronization of the watermark.

Claims

1. A method of encoding a digital watermark in a media signal comprising:

performing a wavelet decomposition of the media signal into two or more levels of resolution, including an approximate level and one or more higher resolution levels; and

modifying the approximate level to encode an auxiliary signal such that the modification is substantially imperceptible in an output form of the media signal, the auxiliary signal serving to carry two or more message symbols and forming peaks in a transform domain used to perform synchronization of the auxiliary signal.

2. A computer readable medium having software for performing the method of claim 1.

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

performing a wavelet decomposition of the media signal into two or more levels of resolution, including an approximate level and one or more higher resolution levels; and

detecting the auxiliary information from the approximate level, including detecting a pattern of peaks in a transform domain to perform synchronization of the auxiliary signal.

4. A computer readable medium having software for performing the method of claim 3.

5. A method of embedding a digital watermark into a media signal so that the digital watermark is substantially imperceptible to a human in the embedded media signal, the method comprising:

performing a wavelet decomposition of the media signal; and

embedding a watermark into the wavelet decomposition such that the watermark signal forms a pattern in a transform domain used to perform synchronization of the watermark, wherein the pattern has attributes used to determine orientation of the watermark in a geometrically distorted version of the media signal;

wherein the pattern used to perform synchronization comprises attributes that both carry two or more auxiliary message symbols in the watermark, and are used to perform synchronization of the watermark.

6. The method of claim 5 wherein the watermark is repeated in blocks throughout the media signal.

7. A computer readable medium having software for performing the method of claim 5.

8. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary signal is substantially imperceptible in an output form of the media signal, the method comprising:

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

synchronizing a reference signal with the wavelet decomposition of the media signal to determine orientation of the auxiliary signal in the media signal, wherein the auxiliary signal forms a pattern in a transform domain used to perform synchronization and the pattern has attributes used to determine orientation of the watermark in a geometrically distorted version of the media signal, wherein the pattern used to perform synchronization comprises attributes that both carry two or more auxiliary message symbols in the watermark, and are used to perform synchronization of the watermark.

9. A computer readable medium including software for performing the method of claim 8.

10. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary signal is substantially imperceptible in an output form of the media signal, the method comprising:

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

synchronizing a reference signal with the wavelet decomposition of the media signal to determine orientation of the auxiliary signal in the media signal, wherein the auxiliary signal forms a pattern in a transform domain used to perform synchronization and the pattern has attributes used to determine orientation of the watermark in a geometrically distorted version of the media signal, including;

performing multi-level synchronization between the reference signal and the wavelet decomposition.

11. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary signal is substantially imperceptible in an output form of the media signal, the method comprising:

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

synchronizing a reference signal with the wavelet decomposition of the media signal to determine orientation of the auxiliary signal in the media signal, wherein the auxiliary signal forms a pattern in a transform domain used to perform synchronization and the pattern has attributes used to determine orientation of the watermark in a geometrically distorted version of the media signal, including;

performing synchronization at an initial low level of resolution of the wavelet decomposition; and

refining results of the synchronization at least one higher level of resolution of the wavelet decomposition.

12. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary signal is substantially imperceptible in an output form of the media signal, the method comprising:

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

synchronizing a reference signal with the wavelet decomposition of the media signal to determine orientation of the auxiliary signal in the media signal, wherein the auxiliary signal forms a pattern in a transform domain used to perform synchronization and the pattern has attributes used to determine orientation of the watermark in a geometrically distorted version of the media signal, including;

performing synchronization at subbands within a level of resolution of the wavelet decomposition;

and combining results of the synchronization at the subbands.

13. A method of detecting an auxiliary signal embedded in a media signal, where the auxiliary signal is substantially imperceptible in an output form of the media signal, the method comprising:

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

synchronizing a reference signal with the wavelet decomposition of the media signal to determine orientation of the auxiliary signal in the media signal, wherein the auxiliary signal forms a pattern in a transform domain used to perform synchronization and the pattern has attributes used to determine orientation of the watermark in a geometrically distorted version of the media signal, including;

performing a polar resampling of at least one level of resolution; and

performing synchronization on the resampled level of correlation.