| 摘要 |
PURPOSE:To efficiently record the monitoring information by detecting a change every frame of a certain scanning line, changing a recording speed in a recorder and changing a recording time resolution to record in detail an image information required for monitoring. CONSTITUTION:A q1 frame of a video signal of l-th scanning line of a video camera signal and the video signal of the l-th scanning line of the next q2 frame are outputted from an AD converter 31, impressed to a memory circuit 31 and a digital comparator 33 and the digital signals are compared. Herein, the information of the l-th scanning line, when a criminal such as a thief invades is different between the q1 frame and the q2 frame. At this time, an output of the digital comparator 33 is fed to an intermittent type VTR sequency control circuit 16 and the existing 480H mode is changed over to 24H mode or 12H mode. Then, when the thief disappears and the information of the the scanning line of the respective frames does not change, the mode is returned to the 480H mode.
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