| 摘要 |
An apparatus for detecting weak beams in an beam detection system includes a plurality of emitters for radiating beams of energy, a plurality of detectors for providing detector signals in response to the beams of energy radiated by said plurality of emitters and means for detecting if the beams radiated by said plurality of emitters are weak. If weak beam is detected, the beam is determined inoperative by the obstruction detection system and is not considered in subsequent obstructiondetection. |
