| 摘要 |
<p>An obstacle detector mounted on an automotive vehicle includes a light emitting element, which includes a semiconductor infrared laser, which transmits a light signal through an optical transmission system against any obstacle liable to present on the road on which the vehicle runs. The light signal has a wavelength which is 6.5 microns and which is of such a wavelength that solar light energy having the same wavelength as that of the light signal is not present, or is of very low intensity, at the surface of the earth and that the light energy from light sources such as the headlights of vehicles and/or streetlamps having substantially the same wavelength as that of the light signal, when the light energy has passed through the front glass of the headlights or streetlamps is not present or is of very low intensity. An optical receiving system receives part of the light reflected by the obstacle and passes it to an optical filter which has a pass band width whose central wavelength is 6.5 microns. The output of the filter is converted by a photodetector to a corresponding electrical signal for processing by a data processor in order to determine the distance from the vehicle to the obstacle, the azimuth of the obstacle, the velocity of the vehicle relative to the obstacle, etc.</p> |
