If {TAIL ~ the value} of 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 {HEAD ~ the white dot counter} 96 
If { TAIL ~ the value } of 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 { HEAD ~ the white dot counter } 96
OTH 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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH