A basic experiment for image-based position measurement of objects at sea

This paper presents an image-based position measurement of underwater objects using a low-cost maritime mobile robot with a monocular camera. Visual recognition of distant underwater objects is possible in the water with high transparency, for example, in the coastal sea area of Okinawa prefecture, Japan. In this paper, we apply the proposed method to estimate the position of an old anchor that is at a deep of 30 [m] and is estimated to be hundreds-of-years-old in an archaeological site in Ishigaki Island. We explain the measurement principle of the proposed method and the developed system. Moreover, we describe the experiment conducted off the coast of Ishigaki Island and show the experimental results of the proposed method.