| 摘要 |
PROBLEM TO BE SOLVED: To detect sticking of stain, when a stain through which a laser beam can be propagated and scattered sticks onto the surface of a laser radar sensor. SOLUTION: When the laser beam is propagated or scattered inside the stain, one portion thereof photoreceived by a photoreception element 83 of the laser radar sensor. The deposition of the stain is determined with the provision that a measuring time from emission up to the reception of reflected beam out of the plurality of emitted laser beams is shorter than a prescribed measuring time, and that the number of the laser beams having intensity of exceeding an upper threshold V1 is the first prescribed number or more in photoreceived pulses of the reflected beam. The reflected beam caused by the stain is estimated to exist when the time from the emission up to the photoreception is shorter than a prescribed measuring time, and a deposition amount of the stain is estimated to be great when the photoreceived pulse has the intensity of exceeding an upper threshold V1. The sticking of a stain is judged thereby when the number of the photoreceived pulses exceeds the first prescribed number. COPYRIGHT: (C)2005,JPO&NCIPI |
