HEAD TRACKER SYSTEM

摘要

A head tracker system for determining a user's head orientation relative to a datum (22) comprises: a head mounting (2) for attachment to the user's head; an optical sensor (12) which in use is located in fixed relation with a know n fixed point relative to the head mounting (2) and a plurality of distinguishable markings (18a-18j) each of which when in use is located in fixed relation with a respective known point which is fixed relative to the datum (22). The head tracker further comprises an optical correlator (26) fo r optically correlating the optical image from the optical sensor (12) with an optical image representative of at least one of said markings (18a-18j); and means (28) for determining the orientation of the head mounting using the output from the optical correlator when it detects that there is correlation between the images.