1. Valentin M. Gelikonov

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    1. Mentioned In 59 Articles

    2. Measurement and Compensation for the Amplitude and Phase Spectral Distortions of an Interference Signal in Optical Coherence Tomography for the Relative Optical-Spectrum Width Exceeding 10%

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      Measurement and Compensation for the Amplitude and Phase Spectral Distortions of an Interference Signal in Optical Coherence Tomography for the Relative Optical-Spectrum Width Exceeding 10%
      We describe a universal method of compensating for the arbitrary dispersion in the spectral and time domain optical coherence tomography systems. In combination with the amplitude method of correcting the optical-spectrum irregularities, this approach allows one to obtain the spectrally determined resolution if the instrument function is close to the Gaussian one. The efficiency of the method is demonstrated in the time and spectral domain optical coherence tomographies with the ...
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      Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov

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

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      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 ...
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      Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov

    4. Time domain optical coherence tomography is a useful tool for diagnosing otitis media with effusion

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      Time domain optical coherence tomography is a useful tool for diagnosing otitis media with effusion
      The usability of time-domain optical coherence tomography equipped with a flexible endoscopic probe for detecting effusion in the tympanic cavity is shown in the clinical environment. The possibility of assessing the dynamic properties of effusion, particularly its contained scatterers' mobility, is shown in real clinical cases. A method of comparative assessment of scatterers' mobility is proposed.
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      Mentions: Natalia M. Shakhova Nizhny Novgorod State Medical Academy Institute of Applied Physics

    5. Optical coherence tomography‐based angiography device with real‐time angiography B‐scans visualization and hand‐held probe for everyday clinical use

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      Optical coherence tomography‐based angiography device with real‐time angiography B‐scans visualization and hand‐held probe for everyday clinical use
      This work is dedicated to the development of the OCT system with angiography for everyday clinical use. Two major problems were solved during the development: compensation of specific natural tissue displacements, induced by contact scanning mode and physiological motion of patients (eg, respiratory and cardiac motions) and online visualization of vessel cross‐sections to provide feedback for the system operator.
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      Mentions: University of Toronto Natalia M. Shakhova I. Alex Vitkin

    6. Cross-Polarization Optical Coherence Tomography with Active Maintenance of the Circular Polarization of a Sounding Wave in a Common Path System

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      Cross-Polarization Optical Coherence Tomography with Active Maintenance of the Circular Polarization of a Sounding Wave in a Common Path System
      We consider a cross-polarization optical coherence tomography system with a common path for the sounding and reference waves and active maintenance of the circular polarization of a sounding wave. The system is based on the formation of birefringent characteristics of the total optical path, which are equivalent to a quarter-wave plate with a 45 orientation of its optical axes with respect to the linearly polarized reference wave. Conditions under which ...
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      Mentions: University of Toronto I. Alex Vitkin Nizhny Novgorod State Medical Academy

    7. Equidistant Recording of the Spectral Components in Ultra-Wideband Spectral-Domain Optical Coherence Tomography

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      Equidistant Recording of the Spectral Components in Ultra-Wideband Spectral-Domain Optical Coherence Tomography
      We develop an effective method for reducing nonequidistance when recording the spectral components of an interference signal in ultra-wideband spectral-domain optical coherence tomography. For this purpose, a corrector consisting of two identical prisms is used in a diffraction-grating spectrometer. The corrector rotation with respect to the diffraction-grating plane and a variation in the angle between the corrector elements allow one to adjust the equidistant spatial distribution of the spectral components ...
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      Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov

    8. A data-acquisition and control system for spectral-domain optical coherence tomography with a speed of 91 912 A-scans/s based on a USB 3.0 interface

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      A data-acquisition and control system for spectral-domain optical coherence tomography with a speed of 91 912 A-scans/s based on a USB 3.0 interface
      We describe a system of optical spectrum registration at the output of an interferometer with controlled phase shifts for an experimental device intended for visualizing the internal structure of an optically turbid specimen, using the method of spectral domain optical coherence tomography. A device for spectral domain optical coherence tomography based on a common-path optical scheme with a USB 3.0 interface for inputting data into a computer has been ...
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      Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov

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

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      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 mediums chromatic dispersion on point-spread function broadening in optical coherence tomography. This enables compensation of the impact ...
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      Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov

    10. Pixel classification method in optical coherence tomography for tumor segmentation and its complementary usage with OCT microangiography

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      Pixel classification method in optical coherence tomography for tumor segmentation and its complementary usage with OCT microangiography
      A novel machine-learning method to distinguish between tumor and normal tissue in optical coherence tomography (OCT) has been developed. Pre-clinical murine ear model implanted with mouse colon carcinoma CT-26 was used. Structural-image-based feature sets were defined for each pixel and machine learning classifiers were trained using ground truth OCT images manually segmented by comparison with histology. The accuracy of the OCT tumour segmentation method was then quantified by comparing with ...
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      Mentions: University of Toronto Felix I. Feldchtein I. Alex Vitkin

    11. Vessel-contrast enhancement in label-free optical coherence angiography based on phase and amplitude speckle variability

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      Vessel-contrast enhancement in label-free optical coherence angiography based on phase and amplitude speckle variability
      Recently proposed in vivo label-free optical coherence angiography techniques based on phase and amplitude speckle variability often require additional signal pre- and post processing operations to enhance vessel-contrast. We observe here 1) contrast enhancement by optimizing the signal normalization/weighing before processing; 2) algorithm based on Kasai estimator for phase compensation between processed A-scans to reduce masking role of motion artifacts; and 3) image projection through the imaging depth for ...
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      Mentions: University of Toronto I. Alex Vitkin Nizhny Novgorod State Medical Academy

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

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      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 ...
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      Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov

    13. Multi-modal optical imaging characterization of atherosclerotic plaques

      Explore Wiley Online Library Cardiology
      Multi-modal optical imaging characterization of atherosclerotic plaques
      We combined cross-polarization optical coherence tomography (CP OCT) and non-linear microscopy based on second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) to assess collagen and elastin fibers and other vascular structures in the development of atherosclerosis, including identification of vulnerable plaques, which remains an important clinical problem and imaging application. CP OCT's ability to visualize tissue birefringence and cross-scattering adds new information about the microstructure and composition of the ...
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      Mentions: Ontario Cancer Institute University of Toronto Felix I. Feldchtein

    14. Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography

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      Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography
      Feasibility of speckle tracking in optical coherence tomography (OCT) based on digital image correlation (DIC) is discussed in the context of elastography problems. Specifics of applying DIC methods to OCT, compared to processing of photographic images in mechanical engineering applications, are emphasized and main complications are pointed out. Analytical arguments are augmented by accurate numerical simulations of OCT speckle patterns. In contrast to DIC processing for displacement and strain estimation ...
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      Mentions: Ontario Cancer Institute University of Toronto I. Alex Vitkin

    15. Scan-pattern and signal processing for microvasculature visualization with complex SD-OCT: tissue-motion artifacts robustness and decorrelation time - blood vessel characteristics

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      Scan-pattern and signal processing for microvasculature visualization with complex SD-OCT: tissue-motion artifacts robustness and decorrelation time - blood vessel characteristics
      ...mir Y. Zaitsev ; Grigory V. Gelikonov ; Alexandr L. Matveyev ; Alexander A. Moiseev ; Sergey Y. Ksenofontov ; Valentin M. Gelikonov ; Valentin Demidov ; Alex Vitkin; Scan-pattern and signal processing for microvasculatur...
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      Mentions: University of Toronto I. Alex Vitkin Nizhny Novgorod State Medical Academy

    16. Hybrid M-mode-like OCT imaging of 3D microvasculature in vivo using reference-free processing of complex-valued B-scans

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      Hybrid M-mode-like OCT imaging of 3D microvasculature in vivo using reference-free processing of complex-valued B-scans
      We propose a novel OCT-based method for visualizing microvasculature in 3D using reference-free processing of individual complex-valued B-scans with highly overlapped A-scans. In the lateral direction of such a B-scan, the amplitude and phase of speckles corresponding to vessel regions exhibit faster variability, and thus can be detected without comparison with other B-scans recorded in the same plane. This method combines elements of several existing OCT angiographic approaches, and exhibits ...
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      Mentions: University of Toronto I. Alex Vitkin Nizhny Novgorod State Medical Academy
    17. 1-15 of 59 1 2 3 4 »
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  4. About Valentin M. Gelikonov

    Valentin M. Gelikonov

    Valentin M. Gelikonov graduated from the Gorky State University in 1966 and received his Ph.D. in 1985 and his Dr. Sc. in physics and mathematics in 2007. His fields of scientific interests include high sensitive optical measurements, low coherence fiber-optic interferometry, optical coherence tomography (OCT). He is Head of Department of Nonlinear Dynamics and Optics at the Institute of Applied Physics RAS. He has published about 120 papers in the fields of laser measurements, fiber-optic interferometry, and OCT. Dr. Gelikonov received the State Prize of the Russian Federation in Science and Technology in 1999.

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