A region of {TAIL ~ an image} having {HEAD ~ a plurality} of corresponding image values is encoded to generate a temporary encoded region 
A region of { TAIL ~ an image } having { HEAD ~ a plurality } of corresponding image values is encoded to generate a temporary encoded region
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH