{TAIL ~ A black area measurement section} measures a black area S by obtaining ratio of {HEAD ~ the number} of pixels satisfying Y≦Y0 in the screen 
{ TAIL ~ A black area measurement section } measures a black area S by obtaining ratio of { HEAD ~ the number } of pixels satisfying Y≦Y0 in the screen
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH