DYNAMIC IMAGE ELECTRONIC WATERMARK SYSTEM

摘要

PURPOSE: To provide the electronic watermark method and system by which the reliability of detecting embedded information is independent of the strength of a signal measured from a frame. CONSTITUTION: In the case of embedding an electronic watermark, information to be embedded is prepared for a bit string (110), a sign of a the bit stream is changed depending on a period of sign inversion (120) and the bit stream is imbedded to a frame (130). Furthermore, in the case of the detection, an observed amount of each frame is stored and the stored observed amount is compared with a variable threshold value corresponding to the stored observed amount to detect the embedded information.