1. Articles from Andrew Weatherbee

    1-4 of 4
    1. Impact of velocity gradient in Poiseuille flow on the statistics of coherent radiation scattered by flowing Brownian particles in optical coherence tomography

      Impact of velocity gradient in Poiseuille flow on the statistics of coherent radiation scattered by flowing Brownian particles in optical coherence tomography

      A closed-form expression is obtained for the temporal correlation function of the scattered radiation detected in optical coherence tomography (OCT), taking into account the flow velocity gradient across the OCT detection volume in the suspension of flowing Brownian particles. The analytical approach we use includes both the laser beam and wavefront curvature radii changing over the depth. Also, we compare our results with a previously obtained theoretical model, partially an empirical approach. Our findings suggest the importance of the flow velocity gradient for accurate measurements of flow velocity vector, particle diffusivity, shear-induced diffusion, and potentially other OCT applications.

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    2. Statistical properties of dynamic speckles from flowing Brownian scatterers in the vicinity of the image plane in optical coherence tomography

      Statistical properties of dynamic speckles from flowing Brownian scatterers in the vicinity of the image plane in optical coherence tomography

      A closed-form analytical expression is obtained for the spatio-temporal correlation function of the scattered radiation detected in fiber-based optical coherence tomography (OCT), assuming a clean optical system arrangement in the OCT sample arm. It is shown that the transverse flow component causes purely translational speckle motion with the predicted speckle velocity 2x higher than the velocity of the flowing particles as would be observed in the image plane under incoherent illumination. It is also shown that both speckle velocity and speckle radius do not depend on the position of the scattering volume relative to the focal plane, hence the derived ...

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    3. Analysis of scattering statistics and governing distribution functions in optical coherence tomography

      Analysis of scattering statistics and governing distribution functions in optical coherence tomography

      The probability density function (PDF) of light scattering intensity can be used to characterize the scattering medium. We have recently shown that in optical coherence tomography (OCT), a PDF formalism can be sensitive to the number of scatterers in the probed scattering volume and can be represented by the K-distribution, a functional descriptor for non-Gaussian scattering statistics. Expanding on this initial finding, here we examine polystyrene microsphere phantoms with different sphere sizes and concentrations, and also human skin and fingernail in vivo . It is demonstrated that the K-distribution offers an accurate representation for the measured OCT PDFs. The behavior of ...

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    4. Probability density function formalism for optical coherence tomography signal analysis

      Probability density function formalism for optical coherence tomography signal analysis

      The distribution of backscattered intensities as described by the probability density function (PDF) of tissue-scattered light contains information that may be useful for tissue assessment and diagnosis, including characterization of its pathology. In this Letter, we examine the PDF description of the light scattering statistics in a well characterized tissue-like particulate medium using optical coherence tomography (OCT). It is shown that for low scatterer density, the governing statistics depart considerably from a Gaussian description and follow the K distribution for both OCT amplitude and intensity. The PDF formalism is shown to be independent of the scatterer flow conditions; this is ...

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    1-4 of 4
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  2. Topics in the News

    1. (4 articles) Ontario Cancer Institute
    2. (4 articles) University of Toronto
    3. (4 articles) I. Alex Vitkin
    4. (2 articles) University of Waterloo
    5. (2 articles) Kostadinka K. Bizheva
    6. (1 articles) Medical University of Vienna
    7. (1 articles) Harbin Medical University
    8. (1 articles) Université Pierre et Marie Curie
    9. (1 articles) University of Erlangen
    10. (1 articles) Wolfgang Drexler
    11. (1 articles) Adrian G. Podoleanu
    12. (1 articles) Mengyang Liu
    13. (1 articles) Bo Yu
    14. (1 articles) Rainer A. Leitgeb
    15. (1 articles) Angelika Unterhuber
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    Probability density function formalism for optical coherence tomography signal analysis Analysis of scattering statistics and governing distribution functions in optical coherence tomography Statistical properties of dynamic speckles from flowing Brownian scatterers in the vicinity of the image plane in optical coherence tomography Impact of velocity gradient in Poiseuille flow on the statistics of coherent radiation scattered by flowing Brownian particles in optical coherence tomography Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age Direct en-face, speckle-reduced images using angular-compounded Master-Slave optical coherence tomography A case report of a recurrent early and late Bioresorbable vascular scaffold thrombosis: serial angiography and optical coherence tomography findings Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study Functional optical coherence tomography and photoacoustic microscopy imaging for zebrafish larvae Plasma Ceramides in Relation to Coronary Plaque Characterization Determined by Optical Coherence Tomography Retinal neurodegeneration in patients with end-stage renal disease assessed by spectral-domain optical coherence tomography Swept-source optical coherence tomography by off-axis Fresnel transform digital holography with an output throughput of 10 Giga voxels per second in real-time