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

Valentin M. Gelikonov

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1. Mentioned In 61 Articles
2. Compensation for the Influence of Fluctuations in the Distance to the Object During Noncontact Probing in Spectral Domain Optical Coherence Tomography
  
  Explore Home - Springer Sep 14 2019 Otolaryngology
  
  We propose and experimentally test a numerical method for correction of the influence of fluctuations in the distance to objects during noncontact probing in optical coherence tomography. The method is based on the analysis of phase shifts of the neighboring scans, which are due to microscale displacements, and further compensation for these displacements by using phasefrequency correction in the spectral domain. Unlike the known correlation methods, the proposed method does ...
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  Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov
3. Improving the Transverse Resolution of Optical Coherence Tomography with a Finite Impulse Response Filter and a Series of Numerically Refocused Images
  
  Explore Журнал СТМ Jul 11 2019
  
  Among the numerous methods for improving the informative value of the optical coherence tomography (OCT), a special place is taken by the methods for increasing the spatial resolution of the resulting images. Increasing the resolution allows one to identify more clinically significant structures in OCT images and thus improve the diagnostic value of OCT. Since the transverse resolution of OCT images is determined by the physical principles different from those ...
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  Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov
4. 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%
  
  Explore Home - Springer Oct 2 2018
  
  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
5. Digital refocusing in optical coherence tomography using finite impulse response filters
  
  Explore IOPscience Jul 24 2018
  
  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
6. Time domain optical coherence tomography is a useful tool for diagnosing otitis media with effusion
  
  Explore IOPscience Jul 10 2018 Otolaryngology
  
  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
7. Optical coherence tomography‐based angiography device with real‐time angiography B‐scans visualization and hand‐held probe for everyday clinical use
  
  Explore Wiley Online Library Jul 5 2018
  
  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
8. Cross-Polarization Optical Coherence Tomography with Active Maintenance of the Circular Polarization of a Sounding Wave in a Common Path System
  
  Explore Home - Springer May 26 2018
  
  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
9. 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
10. 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
11. 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
12. 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
13. 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
14. 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
15. 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
16. 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
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