COORDINATE INPUT DEVICE, DOCUMENT MANAGEMENT SYSTEM AND INFORMATION DISPLAY MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a coordinate input device and a document management system, that ensure convenience and functionality equivalent to the case of writing on a paper with a writing tool without using a conventional tablet and preventing the read of the coordinate information and document information of an information display medium from being obstructed by retouching. SOLUTION: A code symbol is formed by a water repellent material on the surface of the information display medium 10 which is not water repellent. An image reader 1 optically reads an image including the code symbol on the information display medium 10 and a signal processing part 4 decodes the read code symbol and outputs the coordinate information indicating coordinates on the information display medium and the document information indicating the distinction of the information display medium. The signal processing part 4 calculates the value of at least one of the position, direction and distortion amount of the code symbol in the read image. The signal processing part 4 detects the coordinates of a retouching part on the information display medium 10 on the basis of the output information and the calculated value.