A Noise Cancellation Approach for an Illuminating LEDs Based Short-range Visible Light Sensing System

In this paper, an illuminating LEDs based short-range visible light system is proposed and investigated. The LEDs are used not only as illuminating devices but also as ranging and detecting sensors. In this system, the optical rays emitted from the LEDs are modulated with a predetermined signal at a constant frequency with an initial phase, illuminating to a target. The spatial position information of the target is obtained by measuring and analyzing the backscatter signals form the target. To extend the sensing distance as well as reduce the estimation error, a noise cancellation approach by using multiple periods averaging technique is adopted in this system. The fundamental characteristics of the system employing a commercial available illuminating LEDs have been simulated and analyzed. The numerical results show that with this approach, the sensing distance and the accuracy of the position estimation are significantly improved. As a cost, certain reduction of the acquisition rate is also obtained. However, this acquisition rate is acceptable for the system in a realistic scenario.