Mitsuaki Oshima

Visible light communication using a conventional image sensor

This paper proposes a novel Visible Light Communication (VLC) method. There are currently two types of VLC methods, classified by receiving device: the photosensor-based method and the image sensor-based method, each of which has its own drawbacks. Photosensor-based methods require a dedicated high-speed photosensor and a decoder IC that are not installed in commercial smartphones; on the other hand the communication speeds of image sensor-based methods are very slow. Our VLC method consists of a new image sensor-based receiving method, Line Scan Sampling (LSS), which comprises a sampling procedure that is a thousand times faster than conventional image frame-based sampling, combined with LSS-specific modulation schemes. It realizes lighting communication for smartphone receivers at communication speeds that exceed 1 kbps. Our technology is expected to be applicable to various fields, such as indoor positioning systems, signage translation, distribution of coupons, and vehicle communications. In this paper, we describe the principle of the receiving method, suitable modulation schemes, and the experimentally-measured performance of the system.

Line scan sampling for visible light communication: Theory and practice

This paper proposes a novel visible light communication method which consists of two techniques: a high-speed sampling method called line-scan sampling (LSS) and modulation schemes designed for LSS. LSS utilizes the line scan characteristics of CMOS image sensors and it enables high-speed sampling that is a thousand times faster than image frame-based sampling using conventional smartphones. The modulation schemes compensate for shortcomings of LSS and enable visible light communication without perceptible flicker using both current control and PWM control light sources. In this paper, we describe the principle of LSS and two types of modulation schemes, and discuss their experimentally-measured performance.