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