Optimization methods for the insertion, protection, and detection of digital watermarks in digital data
View Patent ↗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.
1. A method for encoding at least one watermark in a content signal, comprising:
predetermining a number of bits in the content signal to be encoded, based on at least one of a fixed length key and signal characteristics of the content signal; and
encoding the watermark in the predetermined bits.
2. A method for encoding at least one watermark in a content signal, comprising:
locating at least one noise-like signal feature in the content signal; and
encoding the at least one watermark in substantially the same location as the at least one noise-like signal feature.
3. A method for encoding at least one digital watermark in a content signal comprising:
measuring a perceived signal-to-error ratio; and
encoding the at least one watermark in a channel bound by a minimum and maximum signal-to-error level for the content signal.
4. A method for digital watermark encode/decode comprising the steps of:
measuring a perceived signal-to-error ratio; and
encoding at least one watermark in a signal feature that is bound by a minimum and maximum signal-to-error level for the digital signal.
5. A method for encoding watermarks in a digital content signal, comprising:
identifying a plurality of signal features in the digital content signal; and
inserting watermark data in the identified signal features;
wherein the identified signal features are identified from relationships between multiple sample windows in the digital content signal.
6. The method of claim 5 , wherein the signal features have logical relationships with an analog waveform represented by the digital content signal.
7. The method of claim 5 , wherein the signal features comprise mathematical functions of the sample windows.
8. A method for decoding watermarks from a digital content signal, comprising:
identifying a plurality of signal features in the digital content signal; and
decoding watermark data from the signal features;
wherein the signal features are identified from relationships between multiple sample windows in the digital content signal.
9. The method of claim 8 , wherein the signal features have logical relationships with an analog waveform represented by the digital content signal.
10. The method of claim 8 , wherein the signal features comprise mathematical functions of the sample windows.