Digital watermarking with content dependent keys and autocorrelation properties for synchronization

• US 7,366,908 B2
• Filed: 04/30/2001
• Issued: 04/29/2008
• Est. Priority Date: 08/30/1996
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Tewfik, Ahmed
• Primary Examiner(s): Moise; Emmanuel L.
• Assistant Examiner(s): CALLAHAN, PAUL E
• Application Number:
  US10/360,794
• Publication Number:
  US 20040174996A1
• Time in Patent Office: 2,556 Days
• Field of Search: 713/176, 380/201, 380/208, 380/207, 380/279, 705/57, 725/31, 726/26, 726/31, 726/30, 726/32
• US Class Current: 713/176
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G10L 19/02 using spectral analysis, e.g. transform vocoders or subband vocoders
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32165 using cosine transforms
• 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 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/154 Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 19/63 using sub-band based transform, e.g. wavelets
• 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 detection method exploits autocorrelation properties of the watermarked signal that enable synchronization of the digital watermark despite temporal or geometric distortion of the host signal. Other watermark methods employ keys, including a key dependent on the content in which the watermark is embedded and another key that is not dependent on the content.

Claims

1. A method of detecting a digital watermark embedded in a host signal comprising:

receiving the host signal including a media signal and a digital watermark that has been perceptually adapted to the media signal in frequency and non-frequency domains;

processing the host signal with a representation of the digital watermark to compute a measure of the digital watermark; and

based on the measure of the digital watermark, extracting the digital watermark from the host media signal wherein the host signal has autocorrelation properties that enable synchronization of the digital watermark despite temporal or geometric distortion of the host signal.

2. A method of digital watermarking a media signal comprising:

deriving a first key that is a function of the media signal;

generating a digital watermark signal that is a function of the first key and a second key that is not dependent on the media signal;

embedding the digital watermark in the media signal.

3. A method of detecting a digital watermark in a host signal comprising:

obtaining a first key that is a function of the host signal;

generating a representation of a digital watermark from the first key and a second key that is not dependent on the host signal; and

processing the host signal with the representation of the digital watermark to extract the digital watermark from the host signal.