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