The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

Ram Mohan Vasu - One of the best experts on this subject based on the ideXlab platform.

  • Ultrasound-modulated optical tomography: direct recovery of elasticity distribution from experimentally Measured Intensity autocorrelation
    Journal of the Optical Society of America. A Optics image science and vision, 2015
    Co-Authors: K. P. Mohanan, A. K. Nandakumaran, Debasish Roy, Ram Mohan Vasu
    Abstract:

    Based on an ultrasound-modulated optical tomography experiment, a direct, quantitative recovery of Young's modulus (E) is achieved from the modulation depth (M) in the Intensity autocorrelation. The number of detector locations is limited to two in orthogonal directions, reducing the complexity of the data gathering step whilst ensuring against an impoverishment of the measurement, by employing ultrasound frequency as a parameter to vary during data collection. The M and E are related via two partial differential equations. The first one connects M to the amplitude of vibration of the scattering centers in the focal volume and the other, this amplitude to E. A (composite) sensitivity matrix is arrived at mapping the variation of M with that of E and used in a (barely regularized) Gauss-Newton algorithm to iteratively recover E. The reconstruction results showing the variation of E are presented. (C) 2015 Optical Society of America

  • QUANTITATIVE ULTRASOUND-MODULATED OPTICAL TOMOGRAPHY: A DIRECT GAUSS-NEWTON APPROACH TO RECOVER ELASTICITY DISTRIBUTION FROM THE Measured Intensity AUTOCORRELATION
    Neural Parallel & Scientific Computations archive, 2013
    Co-Authors: K. P. Mohanan, A. K. Nandakumaran, Debasish Roy, Ram Mohan Vasu
    Abstract:

    We demonstrate a direct recovery of elasticity distribution from ultrasound-modulated optical tomography data gathered at a single detector. The reconstructions are seen to be of good quality and the convergence of the algorithm quick. We have en route devised a means to estimate the Jacobian needed for this reconstructions which uses both the equations of correlation transport and momentum balance. The inversion scheme uses the Gauss-Newton algorithm resulting in a fast decay of the error to convergence in less than 10 iterations in most of the cases.

K Kikuchi - One of the best experts on this subject based on the ideXlab platform.

Robin Kaiser - One of the best experts on this subject based on the ideXlab platform.

  • Temporal Intensity correlation of light scattered by a hot atomic vapor
    Physical Review A, 2016
    Co-Authors: A. Dussaux, William Guerin, Farrokh Vakili, T. Passerat De Silans, Olivier Alibart, Sébastien Tanzilli, Robin Kaiser
    Abstract:

    We present temporal Intensity correlation measurements of light scattered by a hot atomic vapor. Clear evidence of photon bunching is shown at very short timescales (nanoseconds) imposed by the Doppler broadening of the hot vapor. Moreover, we demonstrate that relevant information about the scattering process, such as the ratio of single to multiple scattering, can be deduced from the Measured Intensity correlation function. These measurements confirm the interest of temporal Intensity correlation to access non-trivial spectral features, with potential applications in astrophysics.

John B Parise - One of the best experts on this subject based on the ideXlab platform.

  • area detector corrections for high quality synchrotron x ray structure factor measurements
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2012
    Co-Authors: L B Skinner, Chris J Benmore, John B Parise
    Abstract:

    Correction procedures for obtaining accurate X-ray structure factors from large area detectors are considered, including subpanel effects, over excited pixels and careful Intensity corrections. Problems associated with data normalization, the use of a pixel response correction from a glass standard and minimization of systematic errors are also discussed. Data from glassy GeSe2 and liquid water Measured with a Perkin Elmer amorphous-Silicon detector are used to demonstrate the effectiveness of these correction procedures. This requires reduction of systematic errors in the Measured Intensity to around the 0.1% level. Published by Elsevier B.V.

  • area detector corrections for high quality synchrotron x ray structure factor measurements
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2012
    Co-Authors: L B Skinner, Chris J Benmore, John B Parise
    Abstract:

    Correction procedures for obtaining accurate X-ray structure factors from large area detectors are considered, including subpanel effects, over excited pixels and careful Intensity corrections. Problems associated with data normalization, the use of a pixel response correction from a glass standard and minimization of systematic errors are also discussed. Data from glassy GeSe2 and liquid water Measured with a Perkin Elmer amorphous-Silicon detector are used to demonstrate the effectiveness of these correction procedures. This requires reduction of systematic errors in the Measured Intensity to around the 0.1% level. Published by Elsevier B.V.

Emma J. Bunce - One of the best experts on this subject based on the ideXlab platform.

  • Jupiter's polar ionospheric flows: Measured Intensity and velocity variations poleward of the main auroral oval
    Geophysical Research Letters, 2003
    Co-Authors: Tom Stallard, Steve Miller, Stanley W. H. Cowley, Emma J. Bunce
    Abstract:

    [1] Recent analysis of high-resolution spectra of Doppler-shifted H3+ emission from the auroral/polar regions of Jupiter revealed a complex wind system, with a persistent auroral electrojet and strong anti-sunward flows in a region of lesser Intensity centred around the magnetic pole [Stallard et al., 2001]. This region, which we have called the Dark Polar Region (DPR), is re-investigated, transforming the observed line-of-sight velocities into a frame of reference fixed with respect to the magnetic pole. The DPR is shown to include a region essentially stagnant in this frame of reference (the f-DPR). We identify it as a region coupled to open magnetotail field lines. There is also a transition region in which the ion velocity returns to corotation (the r-DPR).