In one embodiment, {HEAD ~ the detector} is a low resolution CCD array and the position controller includes an electronic controller and {TAIL ~ a look up table} in a memory that provides adjustment data in response to the signals from the detector 
In one embodiment , { HEAD ~ the detector } is a low resolution CCD array and the position controller includes an electronic controller and { TAIL ~ a look up table } in a memory that provides adjustment data in response to the signals from the detector
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH