Perception of an indoor robot workspace by using CTFM sonar imaging

Ultrasonic sensors have been widely used as time-of-flight range finding systems in mobile robots. Different variations of this scheme lead to robust identification of simple reflector types, like walls, corners and edges. In this paper an alternative approach is attempted, able not only to locate and identify simple reflectors, but to detect and recognize more complicated objects. A more sophisticated sensor, the CTFM sonar, produces an image which corresponds to a range map. The image provides information about the location and type of the reflector. A reflectivity model for planes, corners, and edges is presented and compared with some experimental results. A method to distinguish well structured reflectors from complex objects is then described and the application of the system in a room mapping task is demonstrated