Representing a global map for a mobile robot with relational local maps from sensory data

A method is proposed for representing a global map for a mobile robot by using the descriptions of local maps and their relation. Sensor maps viewed at different locations close to each other are transferred into a local map represented in the object-centered coordinate system. First, the 3-D information of the edges on the floor is obtained at each sensor map (a view) by assuming the camera model and the flatness of the floor. A reliable feature is selected as a reference in the local map on which other edges are mapped. During the motion of the robot, the local map is updated by a motion stereo method until the current reference point disappears from a view. Farther edges must be represented in other local maps when the robot approaches them, since they cannot be located as precisely as closer edges can. Finally, the relationship between local maps in the context of the global map is described. The method has been tested on an indoor scene, and the experimental results are shown