| 摘要 |
<p>PURPOSE:To enable a detecting state to continue even if a vehicle is stopped on a measuring line for a long time by stopping only the renewal of reference road surface level data when a state in which an image pickup means senses a vehicle continues for more than a certain period of time. CONSTITUTION:When a vehicle is detected by comparison of a group of data about brightness along a measuring line with reference road surface level data being held, a detection output is issued. If this detecting state continues for more than a predetermined time, only the renewal of the reference road surface level data is stopped and a vehicle stopping mode is started. When no detection signal is issued, data on the next new measuring line is sampled. The reference road surface level data prior to detection of the vehicle is checked until the departure of the vehicle. The departure of the vehicle is detected by comparison of a pattern of the rate of change of brightness with a pattern of change of a reference road surface, and a detection output is canceled accordingly. Thereafter, the vehicle stopping mode is canceled and renewal to the reference road surface level data that suit the present condition is performed for the next vehicle detection.</p> |
