A digital watermark is a kind of marker covertly embedded in a noise-tolerant signal such as audio or image data. It is typically used to identify ownership of the copyright of such signal. It is the process of hiding digital information in a carrier signal.
In digital watermarking, the signal may be audio, pictures, video, texts or 3D models. A signal may carry several different watermarks at the same time. Also, a digital watermark does not change the size of the carrier signal. It is a passive protection tool. It just marks data, neither degrades it nor controls the access to the data.
Applications
Digital watermarking may be used for a wide range of applications, such as:
• Copyright protection
• Source tracking (different recipients get differently watermarked content)
• Broadcast monitoring (television news often contains watermarked video from international agencies)
Classification
Robust imperceptible watermarks are generally proposed as tool for the protection of digital content, but the creation of it has proven to be quite challenging.
A digital watermark is called robust with respect to transformations if the embedded information may be detected reliably from the marked signal, even if degraded by any number of transformations.
A digital watermark is called perceptible if its presence in the marked signal is noticeable.
Digital watermarking techniques may also be classified based on the length of the embedded message and embedding method.
Watermarking for relational databases
Digital watermarking for relational databases emerged as a candidate solution to provide copyright protection, tamper detection, traitor tracing and maintaining integrity of relational data. Many watermarking techniques have been proposed to address these purposes.
References:
http://en.wikipedia.org/wiki/Digital_watermarking
In digital watermarking, the signal may be audio, pictures, video, texts or 3D models. A signal may carry several different watermarks at the same time. Also, a digital watermark does not change the size of the carrier signal. It is a passive protection tool. It just marks data, neither degrades it nor controls the access to the data.
Applications
Digital watermarking may be used for a wide range of applications, such as:
• Copyright protection
• Source tracking (different recipients get differently watermarked content)
• Broadcast monitoring (television news often contains watermarked video from international agencies)
Classification
Robust imperceptible watermarks are generally proposed as tool for the protection of digital content, but the creation of it has proven to be quite challenging.
A digital watermark is called robust with respect to transformations if the embedded information may be detected reliably from the marked signal, even if degraded by any number of transformations.
A digital watermark is called perceptible if its presence in the marked signal is noticeable.
Digital watermarking techniques may also be classified based on the length of the embedded message and embedding method.
Watermarking for relational databases
Digital watermarking for relational databases emerged as a candidate solution to provide copyright protection, tamper detection, traitor tracing and maintaining integrity of relational data. Many watermarking techniques have been proposed to address these purposes.
References:
http://en.wikipedia.org/wiki/Digital_watermarking
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