OPTICAL VEHICLE SENSING DEVICE, OPTICAL VEHICLE SPEED MEASURING DEVICE, OPTICAL VEHICLE SENSING METHOD AND OPTICAL VEHICLE SPEED MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To more precisely sense a vehicle and measure vehicle speed by preventing the erroneous sensing of a vehicle. SOLUTION: Similar processings are separately conducted in parallel on the upstream-side and the downstream-side of a nearside lane. When the calculated height of a reflected point is larger than a threshold, a sensing signal is outputted (S411) and time and height at that time are stored (S413). A vehicle profile is generated by repeating the processing (S411 and S413). The output number of the sensing signals is counted (S415). When a count value exceeds the threshold within prescribed time (S403 and S421), it is judged whether the vehicles sensed on the upstream-side and the downstream-side are the same or not (S435). When it does not exceed the threshold within prescribed time, the sensing signal outputted during that time is canceled (S431). When the generation of the vehicle profile is terminated and it is judged that the vehicles are the same, pass speed is calculated based on the profiles of the upstream-side and the downstream-side (S430).