| 摘要 |
PURPOSE:To prevent influence of a laser reflected ray due to atmospheric scattering particle etc. in a short distance, by inserting an optical attenuation filter in front a photoelectric converter automatically, when a distance of a target object is reduced less than a prescribed distance. CONSTITUTION:Light from a laser oscillator 2 is emitted to a target object through a transmitting optical system 1, and its reflected ray is detected by a photoelectric converter 5 through a reception optical system 4. An output of the photoelectric converter 5 is inputted to a distance computer 9 through a video amplifier 6, and a distance to the target object is calculated. In case the distance to the target object is reduced less than a value set by a distance setting device 12, a filter controller 11 inserts an optical attenuation filter 10 in front of the photoelectric converter 5. |
