Decoding methods in LED-to-smartphone bidirectional communication for the IoT

The use of visible light for bidirectional communication between regular smartphones and the small LEDs integrated in most consumer electronics nowadays raises new challenges. In this paper, we enhance the state of the art with an efficient image processing algorithm to accurately detect the LEDs and decode their signal in real time. To enable flash-to-LED communication on non-rooted smartphones, we propose encoding and decoding methods that cope with the inaccurate flashlight clock rate.