Shape Analysis of Particles by an Image Scanner and a Microcomputer: Application to Agglomerated Aerosol Particles [Translated]^†

Abstract

Algorithms are presented for feature extraction of the geometrical shape of particles. The system consists of a microcomputer and an image scanner which scans the micrograph of particles and transmits the compressed image data. Methods for shape analysis are: 1) calculation of fundamental particle shape parameters (Feret diameter, area, perimeter, first moment, second moment), 2) fractal analysis, 3) opening method and 4) separation of circular primary particles from an agglomerate. The connectivity of particle boundary is recognized for five cases (continuation, termination, creation, split and merge), and the fundamental shape features are calculated according to it. The validity and accuracy of these methods are examined by comparing the calculated and theoretical shape parameters for standard figures. A new index is proposed for the description of the structuring elements number of a two-dimensional particle shape in opening analysis.
These methods are applied to the shape analysis of agglomerated aerosol particles generated from an electric furnace and by the CVD method, and it is shown that the fractal dimension as a particle distribution is useful for the quantitative description of shape.

^† This report was originally printed in Earozoru Kenkyu, 2(2), 117-127 (1987) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Japan Association of Aerosol Science and Technology.