The apparatus includes a telecentric lens system positionable at a near end of a hole with an optical axis of the lens system aligned with the axis of the hole to image {HEAD ~ the interior} of {TAIL ~ the hole} 
The apparatus includes a telecentric lens system positionable at a near end of a hole with an optical axis of the lens system aligned with the axis of the hole to image { HEAD ~ the interior } of { TAIL ~ the hole }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL