| 摘要 |
A visibility measuring system which comprises a radiation emitter which is capable of emitting radiation such as laser pulses in the medium in which the visibility range is to be measured, the radiation emitter being rotatable to emit the pulses in varying directions, a number of reflectors which are spaced at differing predetermined distances from the radiation emitter and laterally with respect to one another, and a radiation receiver for receiving and detecting radiation pulses reflected from each reflector; the measuring system including a device responsive to the amplitude of reflected pulses to control the direction of pulse emission from the radiation emitter to reflect from the not more than two reflectors needed to identify the current visibility range. |
