Implementation of a Cost-Efficient Passive Visible Light Sensing Approach for the Determination of Surface Colors

After the successful penetration of light-emitting diodes (LEDs) into the lighting market in the past, nowadays functionalities beyond illumination become more and more of relevance. Recent attempts in this regard focus on communication, localization and most recently also on sensing with light. In this paper, we demonstrate a simple and costeffective approach to identify different surface colors exemplarily shown on a differently colored cube as a passive object and an LED and an RGB sensitive photodiode as emitter and receiver in a visible light sensing setup. We introduce an algorithm, which after successive characterization, measurement and decision-making steps allows the determination of the individual surface colors by an RGB photodiode with high accuracy. We also present a simple correction procedure, which allows maintaining the accuracy in color identification without the need to repeat the timeconsuming characterization step for any change in the lighting conditions. This approach could become part of future visible light communication, positioning and sensing networks, which, besides exchanging information, also detect incidents in their surroundings.