Rotary LED Transmitter for Improving Data Transmission Rate of Image Sensor Communication

Abstract

This study focuses on image sensor communication (ISC), which is a form of visible light communication, using a light-emitting diode (LED) and a camera as the transmitting and receiving device, respectively. In an ISC system, the receiver captures optical signals transmitted by blinking LEDs as an image and demodulates the data using the captured image. The ISC system can spatially separate signals and noises in the image, thus providing superior anti-interference ability. However, because the speed of ISC depends on the shooting speed of the camera, the receiver suffers from a low data transmission rate when a low-speed camera is used. To improve the data rate of ISC, we have developed a rotary LED transmitter. This transmitter cylindrically rotates the blinking LEDs during the exposure time of the camera. The camera captures multiple blinking states of LEDs as afterimages in a single image, thereby increasing the amount of data received per image. In this paper, we propose an ISC system using a rotary LED transmitter and present an experiment for the evaluation of the data rate. The result indicates that the data rate of the rotary LED transmitter is 60 times that of the conventional method.

A study on detection of rotary LED transmitter for image sensor communication

“…Figure 1 shows the system model. The configuration and operation of RLT can be referred to [4]. The transmitter has 9-chip LEDs and changes the blinking pattern every ∆θ [ • ] of rotation.…”

“…RLT sends data by dividing the range of the rotation angle during one rotation. We define this angular range as α [ • ] and set its value to 60 • based on the results of [4]. We set the center of α as 0 • and the left end as +(α/2 − 1) [ • ] and the right end as −α/2 [ • ].…”

“…To solve this problem, we developed a rotary LED transmitter (RLT) (see Fig. 1) [4]. RLT generates afterimages1 of light by moving the LED light of the transmitting signal while blinking.…”

“…We believe that RLT can be attached to devices with rotating mechanisms, such as persistence of vision displays and rotating lights. Although the effectiveness of the communication speed improvement was confirmed by an experiment using RLT in [4], we conducted this experiment assuming that the position of RLT on the image and the coordinates of known. In a real environment, the receiver needs to detect the position of RLT and the coordinates of afterimages before data demodulation.…”

An Optimal Scheme for the Number of Mirrors in Vehicular Visible Light Communication via Mirror Array-Based Intelligent Reflecting Surfaces

“…In the visible light communication (VLC) system, the information is sent by the LEDs' high-speed flashing and transmitted through the channel to the receiver [8][9][10], such as a Photo-Diode (PD) [11], image sensor [12], or high-speed camera [13]. The received optical signal is converted into the electrical signal through photoelectric conversion firstly; then after signal processing, the original information is restored.…”