3-D shape measurement of pipe by range finder constructed with omni-directional laser and omni-directional camera

A lot of plumbings such as gas pipes and water pipes exist in public utilities, factories, power plants and so on. It is difficult for humans to inspect them directly because they are long and narrow. Therefore, automated inspection by robots equipped with camera is desirable, and great efforts have been done to solve this problem. However, many of existing inspection robots have to rotate the camera to record images in piping because a conventional camera with a narrow view can see only one direction while piping has a cylindrical geometry. The use of an omni-directional camera that can take images of 360° in surroundings at a time is effective for the solution of the problem. However, the shape measurement is difficult only with the omni-directional camera. Then, in this paper, we propose a reconstruction method of piping shape by using an omni-directional camera and an omni-directional laser with a light section method and a structure from motion analysis. The validity of the proposed method is shown through experiments.