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 detecting at least one digital watermark using at least one digital filter and at least one key comprising:
a processor for identifying an area of the digital signal that has been affected by the at least one digital filter and a key for detecting the at least one digital watermark; and
a detector for detecting the at least one digital watermark in the digital signal according to the at least one key and the identified area of the digital signal.
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 detector detects at least one digital watermark in the digital signal affected by the digital filter.
5. The system of claim 1 , wherein the detecting of the at least one digital watermark includes selecting an area of the digital signal from a bit-depth delimited area.
6. A process for decoding a plurality of digital watermarks using an encoding level and a key, comprising:
providing a digital signal encoded with a plurality of digital watermarks;
providing at least one key for decoding digital watermarks;
determining an encoding level; and
decoding at least two of the plurality of digital watermarks encoded in the digital signal at substantially the same encoding level based on the at least one key.
7. A process for decoding digital watermarks using a digital filter and a key, comprising:
providing an encoded 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 encoded content signal;
identifying an area of the encoded content signal that will be affected by the digital filter based on at least one measurable difference between the encoded content signal and a counterpart of the encoded content signal selected from the group consisting of the encoded content signal as a digitally sampled stream, the encoded content signal as an analog waveform, and the encoded content signal as a compressed digital signal; and
decoding 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 process for detecting digital watermarks using a digital filter and a key comprising:
providing at least one key for detecting 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
detecting 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 process for decoding digital watermarks using a digital filter and a key, comprising:
accessing at least one key for decoding digital watermarks;
identifying at least one change to the digital signal that will be affected by the digital filter; and
decoding at least one digital watermark based on the at least one change introduced by the digital filter and the at least one key.
10. The process of claim 9 , wherein the decoding 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 decoding 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 decoder for decoding at least a portion of the digital watermark based on the at least one identified change to the digital signal and the embedding location determined by said at least one key.