FIELD: protection of video information against unauthorized copying.
SUBSTANCE: proposed method using watermarks to protect video information against unauthorized copying by changing scale of pattern in the course of copying includes introduction of watermark in original video signal with different scales. Watermark is maintained in each scale for preset time interval sufficient to enable detector circuit in digital-format video recorder to detect, extract, and process information contained in watermark. Watermark scale is changed by end of preset time interval preferably on pseudorandom basis to ensure appearance of each of all scales in predetermined scale variation range as many times as determined in advance. In this way definite scale possessing ability of watermark recovery to initial position and size can be identified and used for watermark detection.
EFFECT: enhanced reliability, facilitated procedure.
24 cl, 7 dwg
