Patent ID: 7502018
Filing Date: 2009-03-10
Classification: G06F

Abstract:
1. A projector associated with an electronic pen including an infrared ray emitter and an ultrasonic wave generator and operated on a whiteboard, and associated with a signal processor having an infrared ray receiver for receiving an infrared ray emitted from said electronic pen, at least two or more ultrasonic wave receivers each for receiving an ultrasonic wave emitted by said electronic pen, and a plurality of light emitting elements disposed substantially at the same positions as said plurality of ultrasonic wave receivers, said projector comprising: projecting means for projecting a plurality of bright spots onto said whiteboard; imaging means for imaging light emitted by said plurality of light emitting elements and said plurality of bright spots; output means for acquiring information on a position of said electronic pen on said whiteboard from an output of said infrared ray receiver and outputs of said ultrasonic wave receivers, acquiring means for acquiring information on positions of said plurality of bright spots on said whiteboard from a picture captured by said imaging means, said picture including the light emitted by said plurality of light emitting elements and said plurality of bright spots, and normalizing means for normalizing the information on the position of said electronic pen on said whiteboard with the information on the positions of said plurality of bright spots on said whiteboard to deliver normalized coordinate data of said electronic pen; wherein said information on the position of said electronic pen on said whiteboard includes: said information on the position of each of said plurality of bright spots on said whiteboard includes: