Teaching a Robot How to Read Symbols

Symbols are used everywhere to help us nd our way and they provide useful information about our world. Autonomous robots that would operate in real life settings could surely bene t from these indications. Research on character recognition have been going on for quite some time now, and demonstrations have been made of machines that can read printed and handwritten characters. To give an autonomous robot the ability to read symbols, we need to integrate character recognition techniques with methods to position the robot in front of the symbol, to capture the image that will be used in the identi cation process, and to validate the overall system on a robot. Our goal is not to develop new character recognition methods, but to address the di erent aspects required in making a mobile robotic platform, using current hardware and software capabilities, recognize symbols placed in real world environment. Validated on a Pioneer 2 robot, the approach described in this paper uses colors to detect symbols, a PID controller to position the camera, simple heuristics to select image regions that could contain symbols, and nally a neural system for symbol identi cation. Results in di erent lighting conditions are described, along with the use of our approach by our robot entry to the AAAI'2000 Mobile Robot Challenge, making the robot attend the National Conference on AI.