IMPROVEMENTS IN OR RELATING TO AN OPTICAL SCANNER FOR DIRECTING ELECTROMAGNETIC RADIATION TO DIFFERENT LOCATIONS WITHIN A SCAN FIELD

A method and apparatus for determining an alignment of an optical scanner for directing an electromagnetic beam to locations within a scan field. The method may include locating a reference element within the scan field of the optical scanner and controlling the optical scanner to cause the electromagnetic beam to be directed to a plurality of different points in the scan field, including at least one point on the reference element. Reflected electromagnetic radiation is detected. The method may include determining when the electromagnetic beam is directed to a reference position in the scan field given by the reference element from a comparison of an intensity of the detected electromagnetic radiation for the different points and determining a corresponding demand signal that causes the optical scanner to direct the electromagnetic beam to the reference position.