Building a 3D world model with a mobile robot: 3D line segment representation and integration

A system whereby a mobile robot in an unknown environment can incrementally build a world model is described. The model discussed is segment-based. A trinocular system is used to build a local map of the environment. A global map is obtained by integrating a sequence of stereo frames taken while the robot navigates in the environment. Emphasis is on the representation of the uncertainty of 3D segments from stereo and on the integration of segments from multiple views. The representation is simple and very convenient for characterizing the uncertainty of segments. A Kalman filter is used to merge matched line segments. An important characteristic of the integration strategy is that a segment observed by the stereo system corresponds only to one part of the segment in space, so that the union of different observations gives a better estimate on the segment in space. The integration of 35 stereo frames taken in a robot room is described