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