Morphology and position measurement of irregular opaque particle with digital holography of side scattering

Abstract

Morphology measurement is essential for a better understanding of irregular particle dynamics. Digital holography of side scattering is applied to measure the morphology and 3D position of pulverized coal particles. The digital holographic recording of particle side scattering is modelled and the formula is verified by experiments. A side scattering holography system is established to record the hologram of pulverized coal particles. The hologram of particles with several scatterers has uneven chirp fringes which is mainly influenced by scatterer shape, while the hologram of particles with multiple scatterers is a superposition of single scatterer fringes with a speckle background which is influenced by both scatterer shape and location. The Moiré pattern which appears easily in digital holography of side scattering is also analyzed. The proposed technique is validated by in-line holography and is proven to have an advantage in the identification of irregular particle morphological and surface features simultaneously.