| 摘要 |
PURPOSE:To detect the position and track of an object in the vicinity of a light source by emitting a flat-plate-shaped laser light in tracking the object, by detecting a reflected light or a scattered light from the object and by measuring an angle of elevation of the object therefrom. CONSTITUTION:When an object 3 comes to a position A at a time t0, a laser element 1 of a laser alarm device tracks the object 3 in the direction of an angle phi1A. A laser element 2 tracks the object 3 in the direction of an angle phi2A. When the object 3 reflects or scatters a laser light of a laser light source, light-sensing units of the laser elements 1 and 2 sense the reflected or scattered laser light. Based on the laser light sensed by the laser elements 1 and 2, the laser alarm device measures a distance to and an angle of elevation of the object. By this measurement, positions, A, B and C of the object 3 at times t0, t1 and t2 can be detected. The track of the object 3 can be determined also from these positions A, B and C. If a time interval is set to be shorter, the track of the object 3 can be determined accurately. |
