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 system for encoding at least one digital watermark using a digital filter and at least one key comprising:
a processor for identifying an area of the digital signal that will be affected by the digital filter and a 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 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 filter.
5. The system of claim 1 , wherein the encoder encodes the at least one digital watermark comprises selecting an area of the digital signal from a bit-depth delimited area.
6. A method for encoding a plurality of digital watermarks using a digital filter and a key, comprising:
providing a digital signal;
providing at least one 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 key.
7. A method for encoding digital watermarks using a digital filter and a key, comprising:
providing a content signal;
providing at least one key to determine an insertion location for at least one digital watermark;
providing a digital filter to be applied to the content signal;
identifying an area of the content signal that will be affected by the digital filter based on at least one measurable difference between the content signal and a counterpart of the content signal selected from the group consisting of the content signal as a digitally sampled stream, the content signal as an analog waveform, and the content signal as a compressed digital signal; 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 key.
8. A method for encoding digital watermarks using a digital filter and a key comprising:
providing at least one 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 a portion of a digital watermark so as to avoid the identified area and determined by said at least one key.
9. A method for embedding digital watermarks using a digital filter and a key, comprising:
accessing at least one key for embedding digital watermarks;
identifying at least one change to the digital signal that will be affected by the digital filter; and
embedding 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 determined by said at least one key.
10. A method for embedding digital watermarks using a digital filter and a key, comprising:
accessing at least one key for embedding digital watermarks;
identifying at least one change to the digital signal that will be affected by the digital filter; and
embedding 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 determined by said at least one key, wherein the embedding of the at least one digital watermark includes selecting an area of the digital signal from the group consisting of a frequency delimited area and a time delimited area.
11. A system for encoding at least a portion of a digital watermark using a digital filter and at least one key comprising:
a processor for identifying at least one change to the digital signal that will be affected by the digital filter and at least one key for determining at least one embedding location; and
an encoder for encoding at least a portion of the 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 embedding location determined by said at least one key.