Watermarking using a plurality of independent watermarks

摘要

A method of embedding a watermark in a picture, wherein the watermark is derived from a combination of substantially independent watermarks or wherein a number of independent watermarks are embedded in each picture. Preferably the expectation value of the watermark is zero. By selecting a number of watermarks from a given set of watermarks a data payload can be carried. In an alternative embodiment a watermark is derived by convolving a key with a plurality of data bits.