In one embodiment, the light sensitive surface of {TAIL ~ the light sensor} integrates light passing through a cross section of the media along {HEAD ~ a scanning path} of the media 
In one embodiment , the light sensitive surface of { TAIL ~ the light sensor } integrates light passing through a cross section of the media along { HEAD ~ a scanning path } of the media
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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH