| 摘要 |
PURPOSE:To increase the recording capacity of a tape by recording a video signal in a recording device only when a video pattern picked up by a monitoring Camera is changed. CONSTITUTION:The contents of n sampling video information obtained from the monitoring camera 1 are alternately extracted in each frame through a synchronizing sepatator circuit 6, a gate circuit 7, a gate pulse generating circuit 8, and a frame switching circuit 9 and stored in memory circuits 11, 12 respectively. Change ditecting circuits 13, 14 compare the information of one frame before with the current information, and at the time of existence of a change, output detection signals. The detection signals are synthesized by a synthesizing circuit 15 and output 4 from a retrigger circuit 16 is inputted to a control signal input terminal 6 and a time generating circuit 17. The output of the circuit 17 is inputted to a multiplex circuit 18 and multiplexed with a video signal outputted from the camera 1 and the multiplexed signal is applied to a recording device 2. Consequently, the recording device 2 is driven to record the video signal outputted from the camera 1. Thus, the recording capacity of the tape can be increased.
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