| 摘要 |
PURPOSE:To execute easily initial value automatic setting and automatic tracking of a background level with high accuracy by using the fluctuating range of the background level at a prescribed period or a mean value of an object level as the background level. CONSTITUTION:A background identification device 1 inputs a degree of change of video di at each 1/30sec and outputs an object feature signal si. In this case, the upper limit (TH2) 10 and the lower limit (TH1) 12 of the di are compared respectively by comparators 11, 13, an OR gate 14 is opened by a trigger pulse outputted from a timing generator 2 only when the measuring region internal processing at each scanning line is finished with TH2<di or TH1>di, and the signal si reaches ''0''. A calculating section 15 takes it as jamming when the space occupying factor of the measuring region is high and it as no jamming when lower, and executes initial value setting and tracking of the degree of change of background by using the fluctuation range of the background level for a prescribed period at a location where the point occupancy factor is near the space occupancy factor at no jamming and using a mean value of the object level when the point occupancy factor is high. |
