on the control signal received by the detection element 1 a and a predefined emission pattern stored within laser pointer element 1 and being known to the camera control unit 9 operation of laser 1 c to emit a sequence of laser light pulses 2 onto the object corresponding to the acquisition frames of the cameras 5 6 and complying with the pre defined emission pattern the facial surface is then scanned by the referencing light beam 2 resulting in light reflections or light spots 3 being produced in sequence on the surface in the drawing only a few such light marks are represented by way of example i e by a line of such light spots however these spots or reflections may also in general be produced individually at suitable locations by appropriately moving pointer 1 1 u2032 before a later treatment the person conducting the treatment can simply takes hold of the light beamer 1 and scans the facial surface with the light beam 2 for some time due to the fast recording in sequence of single images the camera system acquires and detects respective light reflections 3 each arranged in sequence the light path of which for a single light spot is indicated in the drawing by the dot dash line 7 the two cameras 5 6 are able to three dimensionally map the spatial location of the light reflection and the computer system 9 can determine from the data of the detected light marks the position of light spots assigned to the facial surface stored in the computer are the data from.