Methods and apparatus for embedding watermarks

• US 8,085,975 B2
• Filed: 11/05/2009
• Issued: 12/27/2011
• Est. Priority Date: 06/13/2003
• Status: Expired due to Fees

• Current Assignee: Nielsen Company (US) LLC (RR Donnelley & Sons Company)
• Original Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Inventors: Srinivasan, Venugopal
• Primary Examiner(s): Tabatabai, Abolfazl
• Application Number:
  US12/613,334
• Publication Number:
  US 20100046795A1
• Time in Patent Office: 782 Days
• Field of Search: 382/100, 382/232, 382/233, 380/51, 380/54, 380/210, 380/252, 380/287, 370522-527, 713/176, 713/179, 283/72, 283 74- 81, 283/113, 283/901, 283/902, 358/3.28
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G10L 19/0212 using orthogonal transformation
• CPC Class Codes: G10L 25/27 characterised by the analysis technique

Abstract

Methods and apparatus for embedding a watermark are disclosed. An example method for embedding a watermark disclosed herein comprises identifying a transform coefficient associated with a compressed digital data stream, obtaining a mantissa code, and modifying the transform coefficient based on the mantissa code to embed the watermark.

Claims

1. A method for embedding a watermark, the method comprising:

identifying a transform coefficient associated with a compressed digital data stream;

obtaining a mantissa code; and

modifying the transform coefficient based on the mantissa code to embed the watermark, wherein the mantissa code is a first mantissa code, and wherein modifying the transform coefficient comprises substituting the first mantissa code for a second mantissa code associated with the transform coefficient.

2. A method for embedding a watermark, the method comprising:

identifying a transform coefficient associated with a compressed digital data stream;

obtaining a mantissa code; and

modifying the transform coefficient based on the mantissa code to embed the watermark, wherein obtaining the mantissa code comprises;

selecting a code signal frequency to encode to the transform coefficient based on data to be embedded;

obtaining a masking energy associated with the code signal frequency to be encoded to the transform coefficient;

selecting a magnitude for a watermarked transform coefficient associated with the mantissa code based on the masking energy; and

determining the mantissa code based on the magnitude.

3. A method as defined in claim 2 wherein the code signal frequency comprises one or more sinusoidal components, and wherein each sinusoidal component includes a frequency based on a desired code.

4. A tangible article of manufacture, excluding propagating signals and storing machine readable instructions which, when executed, cause a machine to at least:

identify a transform coefficient associated with a compressed digital data stream;

obtain a mantissa code; and

modify the transform coefficient based on the mantissa code to embed a watermark, wherein the mantissa code is a first mantissa code, and wherein the machine readable instructions, when executed, further cause the machine to modify the transform coefficient by substituting the first mantissa code for a second mantissa code associated with the transform coefficient.

5. A tangible article of manufacture, excluding propagating signals and storing machine readable instructions which, when executed, cause a machine to at least:

identify a transform coefficient associated with a compressed digital data stream;

obtain a mantissa code; and

modify the transform coefficient based on the mantissa code to embed a watermark, wherein the machine readable instructions, when executed, further cause the machine to obtain the mantissa code by;

selecting a code signal frequency to encode to the transform coefficient based on data to be embedded;

obtaining a masking energy associated with the code signal frequency to be encoded to the transform coefficient;

selecting a magnitude for a watermarked transform coefficient associated with the mantissa code based on the masking energy; and

determining the mantissa code based on the magnitude.

6. A tangible article of manufacture as defined in claim 5 wherein the code signal frequency comprises one or more sinusoidal components, and wherein each sinusoidal component includes a frequency based on a desired code.

7. An apparatus for embedding a watermark, the apparatus comprising:

an identifier to identify a transform coefficient associated with a compressed digital data stream; and

a modifier to obtain a mantissa code and modify the transform coefficient based on the mantissa code to embed the watermark, wherein the mantissa code is a first mantissa code, and wherein the modifier is to modify the transform coefficient by substituting the first mantissa code for a second mantissa code associated with the transform coefficient.

8. An apparatus for embedding a watermark, the apparatus comprising:

an identifier to identify a transform coefficient associated with a compressed digital data stream; and

a modifier to obtain a mantissa code and modify the transform coefficient based on the mantissa code to embed the watermark, wherein the modifier is to obtain the mantissa code by;

selecting a code signal frequency to encode to the transform coefficient based on data to be embedded;

obtaining a masking energy associated with the code signal frequency to be encoded to the transform coefficient;

selecting a magnitude for a watermarked transform coefficient associated with the mantissa code based on the masking energy; and

determining the mantissa code based on the magnitude.