Coordinate input device and method having first and second sampling devices which sample input data at staggered intervals

Abstract

A coordinate input device interpolates sampling data, using less input data and simpler computing. The input data (coordinate information indicative of an input trace) are sampled both with a predetermined cycle (Tn), and at the end of a predetermined time interval after the sampling of the cycle Tn is complete. As a result of the two different samplings, not only the coordinate point determined by the sampling of cycle Tn, but also information indicative of a tangent vector at each coordinate point on the input trace are obtained. The coordinate point and the associated tangent vector information are thus output, so that a trace more faithful to the input trace is obtained using fewer coordinate points.