In another embodiment, {HEAD ~ the reference picture} is {TAIL ~ a clean reference picture} in a HITS stream 
In another embodiment , { HEAD ~ the reference picture } is { TAIL ~ a clean reference picture } in a HITS stream
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH