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Optical diffraction tomography in fluid velocimetry: the use of a priori information

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journal contribution
posted on 02.06.2008, 16:06 by J. Lobera, Jeremy M. Coupland
Holographic Particle Image Velocimetry (HPIV) has been used successfully to make threedimensional, three-component flow measurements from holographic recordings of seeded fluid. It is clear that measurements can only be made in regions that contain particles, but simply adding more seeding results in poor quality images that suffer from the effects of multiple scattering. Optical Diffraction Tomography provides a means to reconstruct a 3D map of refractive index from coherent recordings of scattered fields with different illumination conditions. Although the Born Approximation limits the applicability of the technique to weakscattering problems, this approach has been used to create three-dimensional images using a Digital Holographic Microscope (DHM). A non-linear optimization technique, the Conjugated Gradient optimisation Method (CGM) has been previously proposed in microwave imaging for strong scattering problems. In this paper we propose a modification of the CGM which uses apriori information to reduce the number of unknown variables that characterize the object to the position of the seeders. Some 2D numerical experiments have been computed, showing promising results and the value of these is fluid velocimetry is discussed.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Citation

LOBERA, J. and COUPLAND, J.M., 2008. Optical diffraction tomography in fluid velocimetry: the use of a priori information. Measurement science and technology, 19 (7), 074013

Publisher

© Institute of Physics

Publication date

2008

Notes

This article was published in the journal, Measurement science and technology [© Institute of Physics]. The definitive version is available at: http://www.iop.org/EJ/journal/0957-0233

ISSN

0957-0233

Language

en