Peak signal selecting circuit and peak signal choice manner and scanning-type confocal microscope

摘要

PURPOSE: To accurately measure the height of a sample by comparing an image signal having a plurality of peaks with a reference signal for counting the occurrence frequency of the peaks, and comparing the frequency with the value of a peak number desired to be measured. CONSTITUTION: An image signal (a) outputted from a photodetector is inputted to a comparator 21, and compared with a reference signal preliminarily established at the preset level. When the signal (a) is above or below the reference signal, the output (b) of the photodetector is changed. Also, a counter 22 counts the frequency of an output change, using the rising section of the output (b), and sends a count signal (c) to a comparator 23. This comparator 23 makes a comparison between the value of a peak number desired to be measured preliminarily stored in a register 24, and the output (c) of the counter 22. When an agreement is found, the comparator 23 outputs an 'H' signal to a switch 20, and an 'L' signal thereto, when no agreement found. Then, the switch 20 selects a connection at A (image signal side), upon receipt of the 'H' signal, and at B (zero level signal) upon receipt of the 'L' signal for outputting respective signals (e) to a maximum brightness value detecting circuit 25.