Patent AT-E401618-T1: [Translated] CODE SENSOR MOUNTING FOR A PEN

A method of estimating a position of nib of a pen relative to an optical sensor removably mounted on the pen. The optical sensor captures at least two images of a coded surface when the nib contacts the coded surface. The images are captured with the nib at a same position on the coded surface and the pen at different orientations relative to the coded surface. From a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image are estimated, and from the estimated rotations and viewing distances, the position of the nib relative to the optical sensor is estimated.