| 摘要 |
Methods and devices are provided to embed imperceptible watermarks into a host content and to subsequently extract embedded watermarks in a manner so as to achieve desired levels of robustness, transparency and security. For a particular host content, a first number of embedding opportunities are used to insert watermarks, which is less than a number of all embedding opportunities within the host content. Watermarks are extracted from a first number of watermark extraction opportunities, which is less than a number of all watermark extraction opportunities associated with the host content. The relationship between the first number of embedding opportunities, the first number of watermark extraction opportunities and the number of all watermark extraction opportunities is such that a circumvention attempt that overwrites watermarks at all extraction opportunities degrades perceptual quality of the host content below a desired perceptual quality level.
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