Method, device and arrangement for inserting extra information

摘要

Disclosed are a method, device (100) and arrangement for inserting extra information in an input signal (111) in the acoustical or visual domain. A representation in the electrical domain is received, a watermark comprising the extra information is generated and a watermark signal (113) representing the watermark is output to the acoustical or visual. There it merges with the input signal (111). Any recording unit (114) which attempts to record the input signal (111) will automatically record the watermark signal (113) as well, so no unwatermarked specimens are made available. The device (100) can be realized as a computer program product, or as a small portable unit, which can be worn by a person to automatically watermark anything he says. The device (100) can be used to protect physical objects against unauthorized taking of photographs, by projecting a visual watermark signal towards the source.