Each second block portion is transform processed to generate {HEAD ~ a plurality} of {TAIL ~ transformed block portions}, and it is determined which transformed block portion is most similar to a preselected first block portion 
of
Each second block portion is transform processed to generate { HEAD ~ a plurality } of { TAIL ~ transformed block portions } , and it is determined which transformed block portion is most similar to a preselected first block portion
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD 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