Drift compensation/parallel minimization

Abstract

The present invention relates to a method of recognizing and evaluating pen positions of an electronic pen with inertial measurement sensors during writing on a two-dimensional writing substrate, comprising: initially specifying a writing coordinate system with two axes X, Y (), which are orthogonal to each other, on the writing substrate () and an axis Z () perpendicular to the two-dimensional writing substrate (), the X axis () defining e.g. the predominant writing direction, and the writing substrate coordinates x, y being defined with respect to said writing coordinate system, and compensating an undesirable drift in the pen position signal of the electronic pen to be output, comprising executing in parallel a coordinate transformation of the azimuthal angle s () and of the inclination angle y () of the electronic pen () into writing substrate coordinates x, y.