If {HEAD ~ the error measure} is less than {TAIL ~ a specified threshold}, then the region is encoded as a skipped region, otherwise the region is encoded as the temporary encoded region 
is less than
If { HEAD ~ the error measure } is less than { TAIL ~ a specified threshold } , then the region is encoded as a skipped region , otherwise the region is encoded as the temporary encoded region
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH