| 摘要 |
PURPOSE:To always set a dynamic range of a signal sent out to a processing circuit, to a prescribed value by controlling a dynamic range of an output signal of a holding device in accordance with a variation of a monitor area based on setting. CONSTITUTION:A video signal from a video camera 7 is held by a holding device 11 responding to a timing generating device 25 of an object detecting circuit 8. A video signal corresponding to a picture of a monitor area of an area corresponding to this setting is compared with a reference value by a comparing and deciding device 28, and whether an object exists or not is decided and detected. When a set area of a monitor area is varied by a range setting circuit 42 of a monitor area adjusting circuit 41, a control signal varied in reverse against a variation of an area is outputted from a dividing circuit 44, a range controlling circuit 46 is controlled, a dynamic range of a signal which is outputted from the device 11 and sent out to an A/D conversion device 26, etc. becomes a prescribed value, and even if the monitor area set contents are varied, whether an object exists or not can be detected satisfactorily without executing an adjustment, etc. |
