118 新しい微粒子ホログラム解析法による粒子位置、粒径の高精度評価

Abstract

A new image analysis method is presented of determining the size and position of particles by in-line holographic technique. The method is based on the mesurement of diameter of circuler fringes of the in-litre hologram of a particle, which is considered to be almost independent on the photographic conditions and films. The method is based also on the detailed calculation of the in-line hologram pattern of a particle by the Fresnel diffraction theory. It is found that fringe diameter divided square root of particle distance is a slowly varying function of far-field number. The order of fringes have been identified by comparing the hologram with the theoretical prediction, then the far-field number can be estimated in a precision of±1. This approximate far-field number can be used to determine the particle position precisely from the measured fringe diameter of the identified order.Precision of the obtained particle coordinate has been examined by a different dual in-line hologram method proposed by us.Particle diameter can also be estimated successfully by applying Silverman et al's method with the accurate value of particle coordinate.