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

Valentin M. Gelikonov

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1. Mentioned In 64 Articles
2. Numerical method for axial motion artifact correction in retinal spectral-domain optical coherence tomography
  
  Explore Home - Springer Jan 18 2020 Ophthalmology
  
  A numerical method that compensates image distortions caused by random fluctuations of the distance to an object in spectral-domain optical coherence tomography (SD OCT) has been proposed and verified experimentally. The proposed method is based on the analysis of the phase shifts between adjacent scans that are caused by micrometer-scale displacements and the subsequent compensation for the displacements through phase-frequency correction in the spectral space. The efficiency of the method ...
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  Mentions: Nizhny Novgorod State Medical Academy Institute of Applied Physics Grigory V. Gelikonov
3. Optical coherence angiography for pre-treatment assessment and treatment monitoring following photodynamic therapy: a basal cell carcinoma patient study
  
  Explore Nature Publishing Group Dec 15 2019 Dermatology
  
  Microvascular networks of human basal cell carcinomas (BCC) and surrounding skin were assessed with optical coherence angiography (OCA) in conjunction with photodynamic therapy (PDT). OCA images were collected and analyzed in 31 lesions pre-treatment, and immediately/24hours/312 months post-treatment. Pre-treatment OCA enabled differentiation between prevalent subtypes of BCC (nodular and superficial) and nodular-with-necrotic-core BCC subtypes with a diagnostic accuracy of 78%; this can facilitate more accurate biopsy reducing sampling ...
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  Mentions: University of Toronto Felix I. Feldchtein I. Alex Vitkin
4. Elimination of Artifacts Caused by the Nonidentity of Parallel Signal-Reception Channels in Spectral Domain Optical Coherence Tomography
  
  Explore Home - Springer Sep 17 2019
  
  We study the causes of artifact appearance in the images obtained by the method of spectral domain optical coherence tomography with parallel reception of the optical-spectrum components, which are manifested in repetition and overlay of the structural elements of the images of the studied medium with a shift in depth. It is shown that nonidentity of the transfer characteristics of the channels of the multichannel photoreceiving elements is one of ...
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  Mentions: Institute of Applied Physics Grigory V. Gelikonov Valentin M. Gelikonov
5. 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
6. 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
7. 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
8. 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
9. 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
10. 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
11. 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
12. 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
13. 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
14. 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
15. 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
16. 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
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