Perimeter receiver fiber optics/elements are spaced apart from {TAIL ~ a central source} fiber optic/element and received light reflected from the surface of {HEAD ~ the object} is measured 
Perimeter receiver fiber optics / elements are spaced apart from { TAIL ~ a central source } fiber optic / element and received light reflected from the surface of { HEAD ~ the object } is measured
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH