If {HEAD ~ the value} of {TAIL ~ the dot signal} has a value greater than the reference data, the comparator 92 determines that the signal represents a white dot, and generates a white dot signal, which is supplied to the white dot counter 96 
If { HEAD ~ the value } of { TAIL ~ the dot signal } has a value greater than the reference data , the comparator 92 determines that the signal represents a white dot , and generates a white dot signal , which is supplied to the white dot counter 96
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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH