The apparatus further includes a camera arranged to receive an image of the illuminated interior of {HEAD ~ the hole} from {TAIL ~ the telecentric lens system} 
The apparatus further includes a camera arranged to receive an image of the illuminated interior of { HEAD ~ the hole } from { TAIL ~ the telecentric lens system }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL