Video signal movement detection device for video monitoring system

摘要

The device includes three units (1,2,4) for selecting a line from the video picture provided by a monitoring camera. The video signal (Vin) is passed to one unit (1) that separates the vertical synchronising pulse from the signal. The result of this goes to a mono-flop unit (2), triggered by this pulse, to produce a switching signal for a switch (4), closing or opening it. The resulting signal, including one or more lines of the picture, is passed to filter (5) with a certain time constant and also to filter (6) with a different time constant in parallel with it. The difference between the output is formed by differentiator unit (7) and compared in a comparator unit (9) with a threshold value. If this is exceeded, an alarm is given.