Visual Topological Mapping

We present an outdoor topological exploration system based on visual recognition. Robot moves through a graph-like environment and creates a topological map, where edges represent paths and vertices their intersections. The algorithm can handle indistinguishable crossings and close loops in the environment with the help of one marked place. The visual navigation system supplies path traversing and crossing detection abilities. Path traversing is purely reactive and relies on color segmentation of an image taken by on-board camera. The crossing passage algorithm reports azimuths of paths leading out of a crossing to the topological subsystem, which decides what path to traverse next. Compass and odometry is then utilized to move the robot to the beginning of picked path. The proposed system performance is tested in simulated and real outdoor environment using a P3AT robotic platform.