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

  • US 5,889,868 A
  • Filed: 07/02/1996
  • Issued: 03/30/1999
  • Est. Priority Date: 07/02/1996
  • Status: Expired due to Term
First Claim
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1. A method for amplitude independent encoding of digital watermark information in a signal, comprising steps of:

  • determining in said signal a sample window having a minimum and a maximum;

    determining a quantization interval of said sample window, where said quantitization interval can be used to quantize normalized window samples;

    normalizing the sample window to provide normalized samples, where normalized samples conform to a limited range of values, proportional to real sample values, and comprise a representation of the real sample values with a resolution higher than the real range of values, and where the normalized values can be divided by the quantization interval into distinct quantization levels;

    analyzing the normalized samples to determine quantization levels;

    comparing the message bits to the corresponding quantization level information from the analyzing step;

    when a bit conflicts with the quantization level, adjusting the quantization level of said sample window to correspond to the message bit; and

    de-normalizing the analyzed normalized samples.

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