obtaining as {TAIL ~ a gray level ratio} {HEAD ~ a ratio} of calculation result of the left area to calculation result of the right area 
obtaining as
obtaining as { TAIL ~ a gray level ratio } { HEAD ~ a ratio } of calculation result of the left area to calculation result of the right area
REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH