The main subject of this research and development is to make the research and development and proving experiment of the underwater communications (underwater visible light communications =VLC) with the premise of utilization of VLC for tourism and environmental protection, in the oceanic conditions of Okinawa area (Zamami-village) that obtains one of the highest popularities as a diving spot which has the highest transparency of water and gathers lots of coral and fish.
Radio communication is rarely used as a communications tool underwater because the attenuation rate of radio signal is high.
At this moment the only communications tool available in the water is the sonic (ultra-sonic) communications, though, it has not spread out among the divers since it is subject to noises from the reflections of water surface or the bottom of the sea and the handling is not that easy.
Another disadvantage of this mode of communication is that it is very difficult identity the speaker when several divers are present in the same area.
With the underwater VLC device, most of the underwater communications problems are already solved with the following reasons: (1) easy to move and act without cables; (2) it is easier to catch the other buddy's words since it doesn't spread out like sonic communications; (3) conversation is much easier since the buddy can recognize the speaker with eyes.
J-STAGEがリニューアルされました！https://www.jstage.jst.go.jp/browse/-char/ja/
