More precisely, {HEAD ~ the comparator} 92 compares {TAIL ~ the density} represented by each dot signal, with the reference density represented by the reference data 
compares
More precisely , { HEAD ~ the comparator } 92 compares { TAIL ~ the density } represented by each dot signal , with the reference density represented by the reference data
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH