Patent ID: 6999061

Claim:
An electronic whiteboard system comprising a computer unit, an electronic whiteboard, and a projector which projects image data of the computer unit onto the screen of the electronic whiteboard, wherein said electronic whiteboard comprises: coordinate detection means for detecting and determining coordinate information of a position of an electronic pen on the screen; and communications means for reporting coordinate information on the screen detected by said coordinate detection means to a computer unit, and said computer unit comprises: communications means for receiving said coordinate information from the electronic whiteboard; projected position information setting means for setting projected position information of a PC screen image projected onto the screen of the electronic whiteboard by the projector; projected position information storage section for storing said projected position information; desktop operation/drawing means for enabling operation including drawing free lines on the PC screen image projected on the screen based on said coordinate information and said projected position information as well as storing individual stroke information of each of the free lines drawn on the PC screen image in correspondence with a base image of the PC screen; document information storage section for storing a pair of said base image and said free lines on a per page basis and storing a plurality of pages as document information; and document information regeneration means for displaying said base image on a display of the computer unit and then sequentially displaying the stroke information of each of said free lines over said base image in the order said free lines were drawn based on the document information stored in the document information storage section.