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Proceedings Paper

Synthetic aperture imaging of objects embedded within scattering media (Conference Presentation)

Paper Abstract

Optical imaging of objects embedded within scattering media such as biological tissues suffers from the strong background noise due to multiple light scattering. The signal strength from the target objects decays exponentially at the length scale of the scattering mean free path, which is typically on the order of 100 micron for biological tissues. As a consequence, targets located at a depth of just a few scattering mean free paths lose their fine details. In this work, we performed synthetic aperture imaging of targets embedded within a scattering medium and demonstrated that the aperture synthesis process can suppress multiple scattering background better than conventional incoherent imaging. In the reflection geometry, we sent planar waves of various incidence angles and recorded the phase and amplitude maps of the reflected waves using off-axis digital holographic microscopy. A He-Ne laser was used as a light source and target objects were sandwiched between scattering layers made of PDMS mixed with polystyrene beads. We converted each reflected images taken at specific incidence angles into the maps of in-plane momentum difference between reflected and incidence waves. We then synthesized the maps in such a way that the scattered waves with the same momentum differences were added together. In this way, single-scattered waves from the targets were added coherently, which made them outgrow the incoherently added multiple-scattered waves. We achieved 1 micron lateral resolution for a target located deeper than four times the scattering mean free path in which conventional incoherent imaging fails to work.

Paper Details

Date Published: 27 April 2016
PDF: 1 pages
Proc. SPIE 9718, Quantitative Phase Imaging II, 971824 (27 April 2016); doi: 10.1117/12.2211535
Show Author Affiliations
Pilsung Kang, Korea Univ. (Korea, Republic of)
Wonshik Choi, Korea Univ. (Korea, Republic of)


Published in SPIE Proceedings Vol. 9718:
Quantitative Phase Imaging II
Gabriel Popescu; YongKeun Park, Editor(s)

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