APPARATUS FOR JUDGING CONTAMINATION OF SENSOR PART COMPRISED IN VEHICLE DETECTOR AND ITS METHOD, IN WHICH HE CONTAMINATION OF THE SENSOR PART IS MONITORED AUTOMATICALLY

摘要

PURPOSE: An apparatus for judging contamination of a sensor part comprised in a vehicle detector and its method are provided to remove misjudgement according to contamination by judging the contamination of the sensor part automatically. CONSTITUTION: The first sensor part(11) has a plurality of light emitting parts and photo detector parts in a vertical direction. The second sensor part(13) has a photo detector part receiving a light signal of the light emitting part of the first sensor part and a light emitting part emitting a light to the photo detector part of the first sensor part. A control part controls the light emitting parts and the photo detector parts of the first and the second sensor part, and detects whether a vehicle passes through a detection space between the first sensor part and the second sensor part. The light emitting parts of the first and the second sensor part operate in a normal light emission mode and a low light emission mode selectively. The control part controls the sensor part to operate in a low light emission mode to judge the contamination of the sensor part.