Estimation of Spray Droplet-Size Distribution Based on Droplet Elongations Reconstructed by Phase Retrieval Holography

Abstract

Gabor holography has a problem of image reconstructed elongation in the optical axis direction. It is known that the elongation length depends on the diameter of the recorded particle and the wavelength of light. In this study, the phase retrieval holography with two holograms is used for reconstruct particle images in numerical simulations and performance test. In numerical simulation, we find the correlation between particle diameter and elongation by measuring the elongation of reconstructed image of particles with given diameters. In the performance test, we record and reconstruct holograms of the particles with the diameter distribution, and measure the elongation of reconstructed particles. Then, we applied the result of numerical experiments to the elongation lengths, and estimate the droplet diameter distribution. As a result, it is shown that this method can estimate particle diameter distribution close to the given distribution.