Thus, {HEAD ~ the output} of {TAIL ~ the imaging optics} 78 includes light from the infrared light source 92 
Thus , { HEAD ~ the output } of { TAIL ~ the imaging optics } 78 includes light from the infrared light source 92
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH