Implementation of Robust Image Sensor Communication Using Light-Trail Surface by Rotating Propeller LED Transmitter

This paper focuses on underwater visible light communication using a camera as a receiver to improve the operational efficiency of remotely operated vehicles that investigate ocean resources. This technology can realize wireless communication underwater, where wireless communication using radio waves is difficult. However, the optical axes between the transmitter and receiver must be correctly aligned before sending data in the underwater environment. We have developed a propeller LED transmitter (P-Tx) to solve this problem. The P-Tx is a rotating device with blinking LEDs. We can generate a pseudo-surface with successive light trails by rotating the P-Tx. This study calls this pseudo surface a "light-trail surface." The receiver can achieve robust transmitter detection by finding the light-trail surface using image processing without mechanical optical-axis alignment. This study also proposes a modulation method using light-trail surfaces. This study develops a prototype P-Tx and implements the proposed schemes. We then perform ISC experiments using the P-Tx and a camera to verify their communication performance.