Abstract: Coordinate values of existing interactive electronic whiteboard often lack portability and flexibility.Therefore,the parameter varies with time and locating definition won’t be high enough.Thus,a revolutionary algorithm of nine points calibration based on ultrasonic infrared was proposed.This kind of algorithm can deal with the fluctuant data received by the receivers on both sides,work out the coordinate values of the probes on the two receivers,set up the coordinate system using one of the coordinate values and make small-range accuracy adjustment through functional fitting so that the location will be more accurate.According to the experiment,the evolutionary algorithm of nine points calibration based on ultrasonic infrared is able to reduce errors efficiently when the locating parameter changes with time.

Key words: Electronic whiteboard,Ultrasonic infrared,Nine points calibration,Locating definition