Robot Mapping with Range camera, CCD Cameras and Thermal Imagers

This paper describes a multispectral data fusion system for real-time telepresence and digital mapping applicable in reconnaissance robotics. The system was developed by our team for CASSANDRA, a robotic group comprising several robots with different features controllable from a single operator station. Special emphasis is put on cooperative mapping and problems arising from the fact that each robot has distinct sensors and computing capabilities; at the same time, however, it is important to stress that all the robots can supply valuable data to the global map. The system is currently able to process distance data, color data, and thermal information, but it is also prepared for extension such that other parts of the electromagnetic spectrum (e.g., the near infrared region) or mission-specific (e.g., radiation) data can be easily added to the map. The fusion quality and map features were studied both theoretically and via field experiments. The data acquisition is performed using a sensor head placed on an Orpheus-X3 robot; both the head and the robot were developed by our working group. The head contains five matrix sensors: a pair of CCD cameras, a pair of thermal imagers, and one TOF camera.