Self-localization and 3-D model construction of pipe by earthworm robot equipped with omni-directional rangefinder

A lot of plumbings such as gas pipes and water pipes exist in public utilities, factories and so on. The use of an omni-directional camera which can take images of 360 deg in surroundings at a time is effective for pipe inspection. However, shape measurement is difficult only with the omnidirectional camera. Therefore, in this paper, we propose a reconstruction method of a piping shape by using a rangefinder constructed with an omni-directional camera and an omnidirectional laser. The rangefinder is mounted on an earthworm robot. Our method calculates 3-D coordinates by the light section method. By integrating the 3-D coordinates with the information of camera motion estimated by the structure from motion technique, the shape of the pipe is reconstructed. The validity of the proposed method is shown through experiments.