| 摘要 |
PURPOSE:To accurately detect a vehicle running on a road without influences of the weather condition, shadows around it, mud, etc. CONSTITUTION:Periodic marks 3 are added on a road surface 2 where a vehicle 1 runs. A line sensor 11 picks up the image of the road surface 2 to generate a variable density analog signal and sends it to an A/D converter 12. This A/D converter 12 converts the received variable density analog signal to a variable density digital signal and sends it to a CPU 13. The CPU 13 takes out a processing program from a ROM 14 and subjects the variable density digital signal to smoothing, minimum and maximum filter processing, difference calculation, shift processing, product calculation, addition processing based on this processing program to generate an addition signal. The CPU 13 discriminates whether the road surface is changed or not based on this addition signal and stores the discrimination result in a RAM 15. Further, the CPU 13 takes out the discrimination result and discriminates whether the vehicle 1 exists or not based on this result. |
