3-D measurement of objects inwater using fish-eye stereo camera

In this paper, we propose a 3-D measurement method of underwater objects using a fish-eye stereo camera. Sensing in aquatic environments is important to maintain underwater structures and research aquatic lives. A 3-D measurement method of objects in water using a fish-eye stereo camera enables underwater robots to execute its task safely with a wide field of view. However, images taken by fish-eye camera have large distortion following projection model. Also, sensing in aquatic environments meets the difficulty that image distortion occurs by refraction of light due to the difference of refractive indices of air, watertight container and water. As to these problems, we introduce a method to correct fish-eye image and a ray tracing method to remove the effect of refraction. Experimental results show the effectiveness of the proposed method.