摘要 |
<p>On the occasion of superimposing a spectrum spread additional information signal obtained by spectrum spreading the additional information such as a duplication preventing control information and a copy right information, etc. to a video signal, the edge portion of an image of the video signal is detected to set the level of a part of the spectrum spread additional information signal higher than the other part in the part corresponding to the edge portion for the purpose of superimposing such additional signal to the video signal. Thereby, the additional information signal can easily be detected, without deteriorating the reproduced image.</p> |