title: Hybrid digital holographic imaging system for three-dimensional dense particle field measurement.
abstract: To apply digital holography to the measurement of three-dimensional dense particle fields in large facilities, we have developed a hybrid digital holographic particle-imaging system. The technique combines the advantages of off-axis (side) scattering in suppressing speckle noise and on-axis (in-line) recording in lowering the digital sensor resolution requirement. A camera lens is attached to the digital sensor to compensate for the weak object wave from side scattering over a large recording distance. A simple numerical reconstruction algorithm is developed for holograms recorded with a lens without requiring complex and impractical mathematical corrections. We analyze the effect of image sensor resolution and off-axis angle on system performance and quantify the particle positioning accuracy of the system. The holographic system is successfully applied to the study of inertial particle clustering in isotropic turbulence.
authors.affiliation: Mechanical and Aerospace Engineering Department, University at Buffalo, 318 Jarvis Hall, Buffalo, New York 14260, USA.
authors.forename: Lujie
authors.initials: L
authors.lastname: Cao
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
authors.forename: Jeremy
authors.initials: J
authors.lastname: de Jong
authors.forename: Scott
authors.initials: S
authors.lastname: Woodward
authors.forename: Hui
authors.initials: H
authors.lastname: Meng