PARTICLE SIZE MEASURING APPARATUS AND METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a particle size-measuring apparatus adaptable even to a granular object to be inspected wherein particles overlap each other closely and capable of reducing calculation cost. SOLUTION: The average value of the brightness of the image signal subjected to A/D conversion of a granular object to be inspected is calculated and a plurality of sets comprising first set values equal to or more than the average value and second set values equal to or less than the average value at least one of which are different from each other are calculated on the basis of the average value. When the image signal subjected to A/D conversion changes across the set value selected according to a predetermined rule among the first and second set values of one set in a horizontal or vertical direction, the pixel thereof is detected as a change point and the number of pixels detected as change points is counted and the particle size of the granular object 10 to be inspected is calculated on the basis of the number of pixels counted as change points with respect to each of a plurality of sets.