1. Articles from Valentine M. Gelikonov

    1-8 of 8
    1. Low-scattering volumes visualisation from optical coherence tomography data and its applications in otolaryngology

      Low-scattering volumes visualisation from optical coherence tomography data and its applications in otolaryngology

      The method for visualization of the low-scattering objects inside the bulk of the high-scattering tissue is presented. The method can contrast the low-scattering object of interest not only from the high scattering surroundings but from the noise region below the tissue image as well. The proposed method was applied for the visualization of the rodent and human cochlea volume.

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    2. Digital refocusing in optical coherence tomography using finite impulse response filters

      Digital refocusing in optical coherence tomography using finite impulse response filters

      A finite impulse response filter, which shifts the focal plane in optical coherence tomography (OCT) images, is proposed. Since several OCT images with the focal plane in various positions can be fused into one image with increased lateral resolution, such a filter facilitates the creation of an OCT system with numerically increased lateral resolution, operating in real-time, i.e. showing one OCT B-scan with increased lateral resolution while collecting data for the next B-scan. Since the proposed real-time resolution enhancement method is phase-sensitive, the method for estimating and compensating phase shifts between consecutive B-scans during data acquisition is also discussed.

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    3. Medium chromatic dispersion calculation and correction in spectral-domain optical coherence tomography

      Medium chromatic dispersion calculation and correction in spectral-domain optical coherence tomography

      A method for determining and correcting distortions in spectral-domain optical coherence tomography images caused by medium dispersion was developed. The method is based on analysis of the phase distribution of the interference signal recorded by an optical coherence tomography device using an iterative approach to find and compensate for the effect of a medium’s chromatic dispersion on point-spread function broadening in optical coherence tomography. This enables compensation of the impact of medium dispersion to an accuracy of a fraction of a radian (units of percent) while avoiding additional measurements and solution of the optimization problem. The robustness of the ...

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    4. Correction of aberrations in digital holography using the phase gradient autofocus technique

      Correction of aberrations in digital holography using the phase gradient autofocus technique

      We propose a method for correcting aberrations in digital holography based on the principles of computational adaptive optics using the phase gradient autofocus technique that demands no reference measurements. The method requires a priori information on the relative positions of the elements of the optical setup. It is applicable for sufficiently smooth optical aberrations. This technique does not impose any restrictions on the magnitude of the scattered optical field phase distortions caused by the object structure. The efficacy of the proposed method is demonstrated through numerical simulation and experimental verification.

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    5. Noniterative method of reconstruction optical coherence tomography images with improved lateralresolution in semitransparent media

      Noniterative method of reconstruction optical coherence tomography images with improved lateralresolution in semitransparent media

      A method of OCT imaging with a resolution throughout the investigated volume equal to the resolution in the best-focused region is described. It is based on summation of three-dimensional scattered field distributions at the wavelengths determined by OCT source spectral decomposition. A method of finding parameters needed for algorithmic realization of the summation is also proposed. The proposed approaches are tested on several model media, including biological ones.

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    6. Feature Of The Week 4/1/12: Russian Institute of Applied Physics Investigates Digital Refocusing in Optical Coherence Tomography Systems

      Feature Of The Week 4/1/12: Russian Institute of Applied Physics Investigates Digital Refocusing in Optical Coherence Tomography Systems

      Over the past few years using electronic post optical detection processing to create a synthetic receiver field-of-view has become a very promising technique for offering improved performance in biomedical optical imaging systems. Various approaches around this basic theme have been used in OCT and non-OCT systems such as synthetic aperture radar, digital holography, and other microscopy techniques.  The approach not only allows for improving the classic depth-of-focus vs lateral resolution tradeoff in OCT systems but offers other promising performance enhancement such as eliminating the need for deformable mirrors in adaptive optics ophthalmic imaging and application benefits in other fields such ...

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    7. Blind deconvolution algorithm for restoration OCT images with diffraction limited resolution

      Blind deconvolution algorithm for restoration OCT images with diffraction limited resolution
      In this paper we describe an algorithm which is able to compensate an unknown defocus. This algorithm has been applied to recovering defocused en-face Optical Coherence Tomography images. Lateral resolution about 5 um has been achieved at distance from focal plane about 10 Rayleigh lengths.. Both numerical simulations and experiment have been performed to demonstrate the ability of the method.
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    8. Tunable semiconductor laser based on interaction between strongly mismatched Fabry-Perot interferometer and waveguide modes

      Tunable semiconductor laser based on interaction between strongly mismatched Fabry-Perot interferometer and waveguide modes
      The method of spectral selection, based on small optical connection between tilted short Fabry-Perot interferometer and semiconductor optical amplifier has been proposed. It was shown, that short Fabry-Perot interferometer under certain inclination reflects back in narrowband lines, typical for transmitted spectrum. This effect has been used for creation swept semiconductor laser with wavelength tuning range 25 nm at central wavelength 1290 nm and coherence length 8 mm.
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    1-8 of 8
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  2. Topics in the News

    1. (8 articles) Institute of Applied Physics
    2. (8 articles) Valentin M. Gelikonov
    3. (8 articles) Grigory V. Gelikonov
    4. (7 articles) Pavel A. Shilyagin
    5. (3 articles) Dmitry A. Terpelov
    6. (1 articles) Elena B. Kiseleva
    7. (1 articles) Carl Zeiss Meditec
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    Tunable semiconductor laser based on interaction between strongly mismatched Fabry-Perot interferometer and waveguide modes Blind deconvolution algorithm for restoration OCT images with diffraction limited resolution Feature Of The Week 4/1/12: Russian Institute of Applied Physics Investigates Digital Refocusing in Optical Coherence Tomography Systems Noniterative method of reconstruction optical coherence tomography images with improved lateralresolution in semitransparent media Correction of aberrations in digital holography using the phase gradient autofocus technique Medium chromatic dispersion calculation and correction in spectral-domain optical coherence tomography Digital refocusing in optical coherence tomography using finite impulse response filters Low-scattering volumes visualisation from optical coherence tomography data and its applications in otolaryngology Non Exudative AMD Imaged With SS-OCT- Extension High space-bandwidth in quantitative phase imaging using partially spatially coherent optical coherence microscopy and deep neural network Optical coherence tomography assessment of macrophages accumulation in non-ST-segment elevation acute coronary syndromes Early disability in ambulatory patients with multiple sclerosis: optical coherence tomography versus visual evoked potentials, a comparative study