Articles that mention Valentin M. Gelikonov -Optical Coherence Tomography News

Valentin M. Gelikonov

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1. Mentioned In 54 Articles
2. Equidistant Recording of the Spectral Components in Ultra-Wideband Spectral-Domain Optical Coherence Tomography
  
  Explore Home - Springer May 15 2018
  
  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
3. 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
  
  Explore Home - Springer Nov 16 2017
  
  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
4. Medium chromatic dispersion calculation and correction in spectral-domain optical coherence tomography
  
  Explore Home - Springer Oct 5 2017
  
  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
5. Pixel classification method in optical coherence tomography for tumor segmentation and its complementary usage with OCT microangiography
  
  Explore Wiley Online Library Aug 29 2017 Oncology
  
  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
6. Vessel-contrast enhancement in label-free optical coherence angiography based on phase and amplitude speckle variability
  
  Explore Conference Proceedings Apr 28 2016 Cardiology
  
  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
7. Correction of aberrations in digital holography using the phase gradient autofocus technique
  
  Explore IOPscience Feb 2 2016
  
  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
8. Multi-modal optical imaging characterization of atherosclerotic plaques
  
  Explore Wiley Online Library Nov 25 2015 Cardiology
  
  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
9. Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography
  
  Explore SPIE | Journal Jul 20 2015
  
  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
10. Scan-pattern and signal processing for microvasculature visualization with complex SD-OCT: tissue-motion artifacts robustness and decorrelation time - blood vessel characteristics
  
  Explore Conference Proceedings Mar 28 2015
  
  ...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
11. Hybrid M-mode-like OCT imaging of 3D microvasculature in vivo using reference-free processing of complex-valued B-scans
  
  Explore arxiv.org Nov 8 2014
  
  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
12. Recent Trends in Multimodal Optical Coherence Tomography. II. The Correlation-Stability Approach in OCT Elastography and Methods for Visualization of Microcirculation
  
  Explore Home - Springer Sep 23 2014
  
  ...r biomedical progress given the complex and heterogeneous nature of real biological tissues. V. Yu. Zaitsev, V. M. Gelikonov, L. A. Matveev, et al., Radiophys. and Quant. Electron., 57, 52, (2014). M. A. Sutton, W. J. ...
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  Mentions: University of Toronto I. Alex Vitkin Nizhny Novgorod State Medical Academy
13. Improvement of lateral resolution of spectral domain optical coherence tomography images inout-of-focus regions with holographic data processing techniques
  
  Explore IOPscience Aug 31 2014
  
  An analogy between spectral-domain optical coherence tomography (SD OCT) data and broadband digital holography data is considered. Based on this analogy, a method for processing SD OCT data, which makes it possible to construct images with a lateral resolution in the whole investigated volume equal to the resolution in the in-focus region, is developed. Several issues concerning practical application of the proposed method are discussed.
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  Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov
14. A model for simulating speckle-pattern evolution based on close to reality procedures used inspectral-domain OCT
  
  Explore IOPscience Aug 17 2014
  
  A robust model for simulating speckle-pattern evolution in optical coherence tomography (OCT) depending on the OCT system parameters and tissue deformation is reported. The model is based on the application of close to reality procedures used in spectral-domain OCT scanners. It naturally generates images reproducing properties of real images in spectral-domain OCT, including the pixelized structure and finite depth of unambiguous imaging, influence of the optical spectrum shape, dependence on ...
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  Mentions: Nizhny Novgorod State Medical Academy Institute of Applied Physics Grigory V. Gelikonov
15. Achromatic registration of quadrature components of the optical spectrum in spectral domain opticalcoherence tomography
  
  Explore IOPscience Jul 31 2014
  
  We have thoroughly investigated the method of simultaneous reception of spectral components with the achromatised quadrature phase shift between two portions of a reference wave, designed for the effective suppression of the 'mirror' artefact in the resulting image obtained by means of spectral domain optical coherence tomography (SD OCT). We have developed and experimentally tested a phase-shifting element consisting of a beam divider, which splits the reference optical beam into ...
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  Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov
16. Combining the correlation-stability approach to OCT elastography with the speckle-variance evaluation for quantifying the stiffness differences
  
  Explore Conference Proceedings May 15 2014
  
  We discuss an advanced variant of the correlation-stability (CS) approach to OCT elastography that is capable of quantifying the stiffness differences. The modified variant is based on natural combination of CS approach with the speckle-variance (SV) approach. It allows one to determine the strain dependence of the normalized speckle intensity variance function for two compared subsets taken from the OCT images corresponding to the initial and deformed states of the ...
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  Mentions: Nizhny Novgorod State Medical Academy Institute of Applied Physics Grigory V. Gelikonov
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