Publications by authors named "I Berezhnyy"

The appearance of non-blood cells circulating in human peripheral bloodstream indicates an abnormal condition. One important category of these cells is circulating endothelial cells (CECs) shed by compromised blood vessels. Clinical applications that measure the blood level of CECs are hindered due to a lack of standardized instruments.

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Recently several polarimetric techniques have been suggested, designed deliberately for automatic whole-field birefringence imaging in photoelastic models with essentially three-dimensional stresses. In general, these techniques are feasible for mapping three optical parameters that determine birefringence in a given case. However, the difficulty in attaining a high level of data accuracy over the whole image persists.

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It is shown that three optical parameters that are necessary for stress computation in integrated photoelasticity can be measured with high accuracy by use of a Fourier polarimetry method. Inasmuch as a photoelastic sample, which is an object of investigation in integrated photoelasticity, is a kind of an elliptic retarder, the technique presented here measures relative retardation delta, azimuth angle theta, and ellipticity angle epsilon instead of the characteristic parameters that traditionally have been used in integrated photoelasticity. The ability of the new technique to provide better accuracy with a simpler setup has been proved experimentally.

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The search for fast, precise, and robust testing techniques remains an important problem in automated full-field photoelasticity. The polarizer-sample-analyzer (PSA)-based three-wavelength polarimetric method presented here employs discrete Fourier analysis and a spectral content unwrapping algorithm to provide completely automatic, simple, fast, and accurate determination of both photoelastic parameters. Fourier analysis of experimental data and a three-wavelength approach reduce the effect of noise and efficiently cope with poor accuracy in regions of both isochromatic and isoclinic maps.

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We present a new method of time-resolved Mueller matrix imaging polarimetry for spatial and temporal characterization of the polarization effects in backscattering from turbid media. The technique allows measuring the time evolution of spatially varying polarization patterns of diffusely backscattered light with picosecond resolution. A series of time-resolved polarization patterns are obtained at various time delays, are analyzed in sequence, and used to separate the polarimetric contributions of different scattering paths.

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