1. Field of the Invention
This invention relates to laser technology, and more particularly, to a polarization-type laser detection system which is capable of distinguishing between a reflected light signal from a target object and a back-scattered light signal from a mass of suspended particles in the air.
2. Description of Related Art
FIG. 1 is a schematic diagram of a conventional laser detection system. As shown, this laser detection system includes a control unit 10, a laser emitter 20, and an optical receiver 30. This laser detection system is used to detect whether any target object is present nearby. In the case of a target object 40 is present nearby, the laser beam from the laser emitter 20 will be reflected back by the target object 40 and received by the optical receiver 30. The received light is then analyzed by the control unit 10 to indicate the presence of the target object 40.
One drawback to the foregoing laser detection system, however, is that, under bad weather conditions when the air is filled with suspended particles, the emitted laser beam from the laser emitter 20 would be scattered back, causing the optical receiver 30 to received a back-scattered light signal that would make the control unit 10 unable to perform the intended target detection. The laser detection system would therefore operate improperly under bad weather conditions.