Patent ID: 6894271

Claim:
A method for operating a positioning apparatus that moves a positioning element for generating an image of a specimen comprising the steps of: a. generating a first and at least one further reference signal, the first reference signal corresponding to a first reference position of the positioning element and the further reference signal to a further reference position of the positioning element; b. generating a first and at least one further estimated value for a present position of the positioning element, the first and the at least one further estimated value being useable for distortion correction of the image; c. transferring the first reference signal and the first estimated value to the positioning apparatus; d. establishing the first reference position using the positioning apparatus, and measuring the present position and generating a position signal based on the measured present position and the first estimated value so as to provide distortion correction of the image; e. transferring the further reference signal to the positioning apparatus; f. transferring the further estimated value to the positioning apparatus; g. establishing the further reference position, and measuring a further present position of the positioning element and generating a further position signal that based on the measured further present position and the further estimated value so as to provide distortion correction of the image.