Patent ID: 6380532
Filing Date: 2002-04-30
Classification: G06M

Abstract:
An object detection system comprising:an emitter which produces a light beam for reflection by objects to be detected; a first photodetector located on one side of the emitter and producing a first signal which indicates an amount of light from the emitter which strikes the first photodetector after reflection by an object; a second photodetector located on the one side of the emitter and producing a second signal which indicates an amount of light from the emitter which strikes the second photodetector after reflection by an object; a third photodetector located on another side of the emitter which is opposite to the one side and producing a third signal which indicates an amount of light from the emitter which strikes the third photodetector after reflection by an object; and a signal processing circuit connected to the first photodetector, second photodetector and third photodetector, and which produces an output signal in response to subtracting the first signal and third signal from the second signal.