Holographic particle image

Meng H, Pan G, Pu Y, Woodward S (2004) Holographic particle image velocimetry from film to digital recording. Meas Sci Technol 15(4) 673-685... 

Figure 7 Principle of HPIV with traditional setup (a) holographic recording of particle ensembles and (b) holographic reconstruction of particle images and their interrogation (Meng et al., 2004).

Barnhart, D.H., Adrian, R.J., and Papen, G.C., Phase-conjugated holographic system for high-resolution particle image velocimetry, Applied Optics, Vol. 33, No. 30, 7159-7170(1994). 

The effective numerical aperture (A Aeff) of the digital holographic microscopy system is used for the determination of transverse and longitudinal size of the reconstructed particle image. The diffraction limit S of the optical system is calculated as (5 = 1.22(/(/AMeff). If dp < 5, the particle imaging is diffraction limited and transverse size of particle image dj pi equals d, i.e.,... 

Optical techniques, i.e., laser Doppler velocimetry O DV), particle image velocimetry (PIV), and holographic PIV, have matured as successful nonintrusive velocity measurement techniques for large-scale applications. Panigrahi et al. [2] obtained the shear stress from PIV measurements by assuming the validity of law of the wall for turbulent flow. In recent years, the p-PIV has matured as a successful velocity measurement technique for MEMS applications [3]. 

The holographic method is a relatively new imaging technique developed about three decades ago. Since then, this method has been used in the study of airborne and liquid-borne particulate systems in their real world environments [21]. In a holographic experiment, images are formed in a two-step process. In the first step, a collimated coherent light is used to illuminate the sample. A hologram is formed by the far-field diffraction patterns of all the particles in the... 

Visual comparison of the holographically recorded radiation pattern of a particle with Mie theory has also been used for particle sizing [71]. Holography has also been used to locate sub-micron particles in a 3-dimensional volume [72] and, in conjunction with an image analyzing computer, to size the droplets in sprays [73]. 

Fig. 1 Intensity variation along the depth (z) of reconstructed volume near the in-focus position (z ,i ) of a particle (diameter = dp) image reconstructed using lensiess digital holography and digital holographic microscopy...

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