The second integrated frame is divided by {TAIL ~ the first integrated frame} to yield {HEAD ~ a range coded pixel intensity image} 
The second integrated frame is divided by { TAIL ~ the first integrated frame } to yield { HEAD ~ a range coded pixel intensity image }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD