Optimization methods for the insertion, protection, and detection of digital watermarks in digital data

• US 7,107,451 B2
• Filed: 02/22/2001
• Issued: 09/12/2006
• Est. Priority Date: 07/02/1996
• Status: Expired due to Term

• Current Assignee: Wistaria Trading Inc.
• Original Assignee: Wistaria Trading Inc.
• Inventors: Moskowitz, Scott A.
• Primary Examiner(s): Smithers, Matthew
• Application Number:
  US09/789,711
• Publication Number:
  US 20010029580A1
• Time in Patent Office: 2,028 Days
• Field of Search: 375/240.03, 713/176
• US Class Current: 713/176
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• CPC Class Codes: G06Q 20/3823 combining multiple encryption tools for a transaction
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: H04L 2209/08 Randomization, e.g. dummy operations or using noise
• CPC Class Codes: H04L 2209/608 Watermarking
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management data processing systems or methods, specially adapted for commerce, e.g. marketing, shopping, billing, auctions or e-commerce G06Q30/00
• CPC Class Codes: H04L 2463/102 applying security measure for e-commerce data processing systems or methods, specially adapted for e-commerce G06Q30/00
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps
• 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

Abstract

Disclosed herein are methods and systems for encoding digital watermarks into content signals. Also disclosed are systems and methods for detecting and/or verifying digital watermarks in content signals.

According to one embodiment, a system for encoding of digital watermark information includes: a window identifier for identifying a sample window in the signal; an interval calculator for determining a quantization interval of the sample window; and a sampler for normalizing the sample window to provide normalized samples.

According to another embodiment, a system for pre-analyzing a digital signal for encoding at least one digital watermark using a digital filter is disclosed.

According to another embodiment, a method for pre-analyzing a digital signal for encoding digital watermarks comprises: (1) providing a digital signal; (2) providing a digital filter to be applied to the digital signal; and (3) identifying an area of the digital signal that will be affected by the digital filter based on at least one measurable difference between the digital signal and a counterpart of the digital signal selected from the group consisting of the digital signal as transmitted, the digital signal as stored in a medium, and the digital signal as played backed.

According to another embodiment, a method for encoding a watermark in a content signal includes the steps of (1) splitting a watermark bit stream; and (2) encoding at least half of the watermark bit stream in the content signal using inverted instances of the watermark bit stream.

Other methods and systems for encoding/decoding digital watermarks are also disclosed.

Claims

1. A system for pre-analyzing a digital signal for encoding at least one digital watermark using a digital filter and at least one pseudo-random key comprising:

a processor for identifying an area of the digital signal that will be affected by the digital filter and a pseudo-random key for mapping the at least one digital watermark; and

an encoder for encoding the at least one digital watermark in the digital signal according to the map of the at least one pseudo-random key, the encoder encoding the at least one digital watermark so as to avoid the at least one area of the digital signal that will be affected by the digital filter.

2. The system of claim 1, wherein the processor operates on the digital signal by selecting an area of the digital signal from the group consisting of a frequency delimited area and a time delimited area.

3. The system of claim 1, wherein the processor operates on the digital signal by selecting an area of the digital signal from a bit-depth delimited area.

4. The system of claim 1, wherein the encoder ensures that the watermark will survive the changes introduced by the digital fitter.

5. A system for analyzing composite digitized signals for watermarks, comprising:

a first receiver for receiving a composite signal and at least one watermark key;

a second receiver for receiving an unwatermarked sample signal;

an aligner for time aligning the unwatermarked sample signal with the composite signal;

an adjuster for gain adjusting the time aligned unwatermarked sample signal to a corresponding segment of the composite signal, determined when the signals are time aligned;

an estimator for estimating a pre-composite signal using the composite signal and the gain adjusted unwatermarked sample signal;

an estimator for estimating a watermarked sample signal by subtracting the estimated pre-composite signal from the composite signal where the specifics of the suspected watermark are unknown and a watermark is not introduced into the estimator;

a scanner for scanning the estimated watermarked sample signal for watermarks; and

a comparator for comparing the suspected watermark with the at least one watermark key.

6. A method for pre-analyzing a digital signal for encoding a plurality of digital watermarks using a digital filter and a pseudo-random key, comprising:

providing a digital signal;

providing at least one pseudo-random key for mapping digital watermarks;

providing a plurality of digital watermarks;

determining an encoding level; and

encoding each of the plurality of digital watermarks in the digital signal at substantially the same encoding level based on the map of the at least one pseudo-random key.

7. A method for pre-analyzing a digital signal for encoding digital watermarks using a digital filter and a pseudo-random key, comprising:

providing a digital signal;

providing at least one pseudo-random key to determine an insertion location of digital watermarks;

providing a digital filter to be applied to the digital signal;

identifying an area of the digital signal that will be affected by the digital filter based on at least one measurable difference between the digital signal and a counterpart of the digital signal selected from the group consisting of the digital signal as transmitted, the digital signal as stored in a medium, and the digital signal as played backed; and

inserting at least a portion of a digital watermark based on the identified area and the insertion location determined by the at least one pseudo-random key.

8. A method for pre-analyzing a digital signal for encoding digital watermarks using a digital filter and a pseudo-random key comprising:

providing at least one pseudo-random key for mapping digital watermarks;

identifying at least one of a frequency and a time delimited area of the digital signal that will be affected by the digital filter; and

encoding at least one digital watermark so as to avoid the identified area and determined by said at least one pseudo-random key.

9. A method for pre-analyzing a digital signal for encoding digital watermarks using a digital filter and a pseudo-random key, comprising:

providing at least one pseudo-random key for inserting digital watermarks;

identifying at least one change to the digital signal that will be affected by the digital filter; and

encoding at least one digital watermark so the watermark survives the changes introduced by the digital filter based on the at least one identified change to the digital signal and the insertion location determined by said at least one pseudo-random key.