a height detector for detecting {TAIL ~ a height} of a surface of {HEAD ~ an object} to be inspected 
a height detector for detecting { TAIL ~ a height } of a surface of { HEAD ~ an object } to be inspected
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH