Field operation of a High-resolution Acoustic Camera on CR200 and Mosaicking

Abstract

This paper describes field operation of a high-resolution acoustic camera on a multi-legged unmanned subsea robot, Crabster200(shortened to CR200). The CR200 has six artificial legs to thrust itself and control its body attitude. The robot is supposed to inspect and work in fast flow and low visible turbid water. In turbid water where optical cameras fail to image anything, acoustic camera can be a substitute. The acoustic camera was installed with a rotator which provides 2 degrees of freedom with roll motion and pitch motion. Yaw motion can be obtained from rotation of CR200 in place. In this paper, operation of the acoustic camera on CR200 in the sea is depicted. The authors have tried to verify the performance of CR200 as an actively adaptable underwater mobile observatory. Two kinds of mosaicking are conducted as well. One is a conventional mosaic using multiple horizontal images. The other mosaic is formed by images grabbed while pitch motion. This provided clues of 3- dim!ensional reconstruction.is supposed to inspect and work in fast flow and low visible turbid water. In turbid water where optical cameras fail to image anything, acoustic camera can be a substitute. The acoustic camera was installed with a rotator which provides 2 degrees of freedom with roll motion and pitch motion. Yaw motion can be obtained from rotation of CR200 in place. In this paper, operation of the acoustic camera on CR200 in the sea is depicted. The authors have tried to verify the performance of CR200 as an actively adaptable underwater mobile observatory. Two kinds of mosaicking are conducted as well. One is a conventional mosaic using multiple horizontal images. The other mosaic is formed by images grabbed while pitch motion. This provided clues of 3- dim!ensional reconstruction.