Method of extracting a watermark

摘要

A monitoring station for monitoring distribution of media content, on basis of a watermark, comprises: receiving means for receiving an information signal representing the media content to which the watermark is added; extracting means for extracting perceptual features, identifying the information signal; first retrieving means for retrieving a supporting signal on basis of the perceptual features; second retrieving means for retrieving the watermark on basis of the supporting signal; and comparing means for comparing the watermark with predetermined information.