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