Method of counting particles using degree of membership in clustering data points into subgroups

Claim 1

A particle counting method comprising: passing plural kinds of particles substantially one at a time through a narrow path; measuring values of at least two kinds of characteristics of each particle in said narrow path; preparing a scattergram of at least two dimensions using said values as parameters thereof; partitioning said particles in said scattergram into clusters of said plural kinds; defining a fixed domain for each cluster of said scattergram so that all of the particles within said domain belong to said cluster without exception and assigning a membership value of one to all particles within said domain; calculating an initial center of gravity of each cluster based upon the spatial distribution of the particles throughout said cluster; calculating a distance from said particle distributed outside each said fixed domain in said scattergram to the initial center of gravity of said cluster and calculating the membership value of said particle to each cluster based upon said distance; correcting said initial center of gravity of each cluster in consideration of the value of membership of each particle distributed outside said fixed domains to each cluster; calculating an estimated number of particles belonging to each cluster based upon the value of membership of each particle in said scattergram to each cluster.