| 摘要 |
PURPOSE:To detect the distance between an optical car speed detector and a car, and to discriminate travelling lane by setting up appropriately the optical pathes of reflected rays from 3 detecting points. CONSTITUTION:A camera 30 inoporates 2 optical systems which are provided with lenses 31 and 32 respectively. The camera 30 is directed to a detecting surface P. The lens 31 includes the 1st and 3rd detecting points P1, P3 which are separated by L2 to each other within its field. The lens 32 detects the 2nd detecting point P2 which is positioned between these detecting points P1 and P2. Respective detecting points P1-P3 are correspondingly provided with photodetectors J1-J3, which detect reflected light when a car with speed V passes through P. If the required time for the distance between P1 and P2 and P2 and P3 are t1 and t2 respectively, the distance (g) between the detector and the car is k1.t2. d2/(k1 .t2-k2.t1) (where, k1 and k2 are constant decided by a1, a2, d1, and d2). Thus, the distance between the car and detector can be measured by t1 and t2. |
