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

• US 6,522,767 B1
• Filed: 03/30/1999
• Issued: 02/18/2003
• 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., Cooperman, Marc
• Primary Examiner(s): Boudreau, Leo
• Assistant Examiner(s): Tabatabai, Abolfazl
• Application Number:
  US09/281,279
• Time in Patent Office: 1,421 Days
• Field of Search: 382/100, 382/232, 380/54, 380/252, 380/210, 380/287, 380/282, 713/176, 713/179, 348/461, 348/463
• US Class Current: 382/100
• CPC Class Codes: H04L 2209/34 Encoding or coding, e.g. Huffman coding or error correction
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 2209/608 Watermarking
• CPC Class Codes: H04L 9/3263 involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823
• 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

The implementations of digital watermarks can be optimally suited to particular transmission, distribution and storage mediums given the nature of digitally-sampled audio, video and other multimedia works. Watermark application parameters can be adapted to the individual characteristics of a given digital sample stream. Watermark information can be either carried in individual samples or in relationships between multiple samples, such as in a waveform shape. More optimal models may be obtained to design watermark systems that are tamper-resistant given the number and breadth of existent digitized sample options with different frequency and time components. The highest quality of a given content signal may be maintained as it is mastered, with the watermark suitably hidden, taking into account usage of digital filters and error correction. The quality of the underlying content signals can be used to identify and highlight advantageous locations for the insertion of digital watermarks. The watermark is integrated as closely as possible to the content signal, at a maximum level to force degradation of the content signal when attempts are made to remove the watermarks.

Claims

1. A method of encoding a digital watermark into a signal, comprising the steps of:

selecting a sample window in the signal;

determining a quantization interval of the sample window, wherein the quantization interval can be used to quantize normalized sample windows;

normalizing the sample window to provide normalized samples, wherein the normalized samples conform to a limited range of normalized values which can be divided by the quantization interval into distinct quantization levels;

analyzing the normalized samples to determine a quantization level;

adjusting the quantization level of a sample window based on an associated portion of the digital watermark; and

de-normalizing the analyzed normalized samples.

2. The method of claim 1, wherein the quantization interval and quantization levels comprise nonlinear quantization information.

3. The method of claim 2, wherein the nonlinear quantization information comprises one of block floating point system, floating point system, nonuniform compounding, adaptive delta modulation, adaptive differential pulse-code modulation and perceptual coding scheme information.

4. The method of claim 2, further comprising the step of:

pre-analyzing a digital sample to evaluate a substantially optimal location for the digital watermark based on a quantization envelope.

5. The method of claim 2, further comprising the step of:

randomly introducing noise significantly above a quantization amplitude on a window-by-window basis.

6. The method of claim 5, wherein the noise is local dither.

7. The method of claim 5, further comprising the step of:

doping the signal to introduce a degree of random errors that do not contain information associated with the digital watermark.

8. The method of claim 2, wherein the digital watermark is further encoded into the signal using a perceptual coding system.

9. The method of claim 8, wherein the perceptual coding system is associated with a compression scheme.

10. The method of claim 9, wherein the compression scheme is one of MPEG-1 and AC-3.

11. A method of decoding a digital watermark from a signal, comprising the steps of:

selecting a sample window in the signal;

determining a quantization interval of the sample window, wherein the quantization interval can be used to quantize normalized sample windows;

normalizing the sample window to provide normalized samples, wherein the normalized samples conform to a limited range of normalized values which can be divided by the quantization interval into distinct quantization levels;

analyzing the quantization level of the normalized samples to determine a portion of the digital watermark.

12. The method of claim 11, wherein the quantization interval and quantization levels comprise nonlinear quantization information.

13. The method of claim 12, wherein the nonlinear quantization information comprises one of block floating point system, floating point system, nonuniform compounding, adaptive delta modulation, adaptive differential pulse-code modulation and perceptual coding scheme information.

14. The method of claim 12, further comprising the step of:

pre-analyzing a digital sample to evaluate a substantially optimal location for the digital watermark based on a quantization envelope.

15. The method of claim 12, further comprising the step of adding dither to the signal.

16. The method of claim 15, wherein the dither is one of triangular probability density function (pdf), Gaussian pdf and rectangular pdf dither.

17. The method of claim 15, wherein the digital watermark is contained in a random-super-level non-subtractive dither.

18. The method of claim 12, wherein the digital watermark is further encoded into the signal using a perceptual coding system.

19. The method of claim 18, wherein the perceptual coding system is associated with a compression scheme.

20. The method of claim 19, wherein the compression scheme is one of MPEG-1 and AC-3.

21. An article of manufacture comprising a machine-readable medium having stored thereon instructions adapted to be executed by a processor, the instructions which, when executed, result in the process:

selecting a sample window in the signal;

determining a quantization interval of the sample window, wherein the quantization interval can be used to quantize normalized sample windows;

normalizing the sample window to provide normalized samples, wherein the normalized samples conform to a limited range of normalized values which can be divided by the quantization interval into distinct quantization levels;

analyzing the normalized samples to determine a quantization level;

adjusting the quantization level of a sample window based on an associated portion of the digital watermark; and

de-normalizing the analyzed normalized samples.

22. An article of manufacture comprising a machine-readable medium having stored thereon instructions adapted to be executed by a processor, the instructions which, when executed, result in the process:

selecting a sample window in the signal;

determining a quantization interval of the sample window, wherein the quantization interval can be used to quantize normalized sample windows;

normalizing the sample window to provide normalized samples, wherein the normalized samples conform to a limited range of normalized values which can be divided by the quantization interval into distinct quantization levels;

analyzing the quantization level of the normalized samples to determine portion of the digital watermark.