Correction of coordinates input by a user through an input device is effected using coordinate correction parameters. To calculate the coordinate correction parameters, a plurality of reference points are displayed on the input device. Coordinate input is designated by a user, and if the coordinate is determined to correspond to a reference point, then the coordinate input is retained. The process is repeated until a coordinate is kept for each reference point, wherein only remaining reference point(s) for which a corresponding coordinate has not yet been retained are displayed. Once coordinates have been input for the reference points, a correspondence between coordinate input and a reference point is determined, and corresponding coordinates are kept for each reference point. Using correction parameters calculated based on the kept coordinates, it is possible to correct device characteristics of the input device such as position aberration, even if such characteristics are non-linear.