Development of multi-wavelength digital holography for highly accurate particle measurement

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06156
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Fluid engineering
• Research Institution: Kyoto Institute of Technology
• Principal Investigator: MURATA Shigeru 京都工芸繊維大学, 機械工学系, 教授 (50174298)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 流体計測 / 波動光学 / ディジタルホログラフィ / ３次元計測 / 粒子計測

Outline of Final Research Achievements

In this research, a high-performance digital holographic system has been developed for simultaneously measuring various quantities on small particles or droplets of about 10 micro meter in diameter distributed in three-dimensional space with high number density. Performance improvement is achieved by applying a phase retrieval technique to color hologram images to eliminate the noisy effect of conjugate image fringes on the background and by employing a new deconvolution technique to suppress the depth elongation of particle image numerically reconstructed from hologram image. Performance tests are carried out in numerical simulation and experiment to show the feasibility of the developed system in particle measurement.

Free Research Field

流体工学

Academic Significance and Societal Importance of the Research Achievements

本研究課題で開発した粒子計測システムを用いると，１台のカメラと波動光学理論に基づく数値処理によって粒子・液滴・気泡群の３次元空間情報を簡便かつ廉価に知ることができる．例えば高密度燃料噴霧の空間分布特性や噴霧粒子特性を同時計測することでエンジンの高効率化や排気ガスのクリーン化を図ることができ，またビデオカメラで観測するため，粒子・液滴・気泡群の３次元空間における運動状態を時系列的に捉えることが出来るため，各種産業界の開発研究や一般の学術研究においてその有用性は極めて大きいと考えられる．