1. Grigory V. Gelikonov

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    1. Mentioned In 86 Articles

    2. Slow axis displacement correction for stripe artefact removal in optical coherence angiography

      Slow axis displacement correction for stripe artefact removal in optical coherence angiography
      The method for displacement correction along the slow axis of optical coherence tomography (OCT) data volumes is presented. The method is based on the recursive replacement of the next displaced OCT measurements by the weighted summation of itself and the previous OCT measurement in the slow axis dimension already corrected for the displacement. The values of the appropriate weight multipliers were defined from the local correlation of the two measurements ...
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    3. Calibration of Lateral Scanning in Optical Coherence Tomography Devices

      Calibration of Lateral Scanning in Optical Coherence Tomography Devices
      Methods for determining the dependence of the lateral-scan coordinate on the A-scan number from tomographic images of test samples are investigated and techniques for compensating for horizontal distortions of tomographic images caused by uneven speed of the probing-beam displacement are proposed. An opal-glass Ronchi ruling and an inclined flat surface of the volume-scattering plate were used as test samples .
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    4. Depth-resolved approach for the attenuation coefficient calculation from the Optical Coherence Tomography data and its application for the brain imaging

      Depth-resolved approach for the attenuation coefficient calculation from the Optical Coherence Tomography data and its application for the brain imaging
      Optical coherence tomography (OCT) is a promising tool for intraoperative tissue morphology determination. Several studies suggest that the attenuation coefficient, derived from the OCT images can differentiate between normal and tumorous tissues, as well as between gray and white brain matter. The methods used for attenuation coefficient derivation in these studies follow the assumption that the optical properties of the specimen are uniform within the OCT imaging depth range. Although ...
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    5. Determination and correction of aberrations in full field OCT using phase gradient autofocus by maximizing the likelihood function

      Determination and correction of aberrations in full field OCT using phase gradient autofocus by maximizing the likelihood function
      A method for numerical estimation and correction of aberrations of the eye in fundus imaging with optical coherence tomography (OCT) is presented. Aberrations are determined statistically by using the estimate based on likelihood function maximization. The method can be considered as an extension of the phase gradient autofocusing algorithm in synthetic aperture radar imaging to 2D optical aberration correction. The efficacy of the proposed method has been demonstrated in OCT ...
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    6. Application of Phase Correction for Compensation of Motion Artifacts in Spectral-Domain Optical Coherence Tomography

      Application of Phase Correction for Compensation of Motion Artifacts in Spectral-Domain Optical Coherence Tomography
      The application of computational methods to correct distortions in spectral-domain optical coherence tomography due to fast probe movements relative to a studied object is described. This technique is intended for use in endoscopy or in the study of external biological tissues using a handheld probe. The effectiveness of the method was confirmed experimentally.
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    7. 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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    8. Numerical method for axial motion artifact correction in retinal spectral-domain optical coherence tomography

      Numerical method for axial motion artifact correction in retinal spectral-domain optical coherence tomography
      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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    9. Optical coherence angiography for pre-treatment assessment and treatment monitoring following photodynamic therapy: a basal cell carcinoma patient study

      Optical coherence angiography for pre-treatment assessment and treatment monitoring following photodynamic therapy: a basal cell carcinoma patient study
      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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    10. Elimination of Artifacts Caused by the Nonidentity of Parallel Signal-Reception Channels in Spectral Domain Optical Coherence Tomography

      Elimination of Artifacts Caused by the Nonidentity of Parallel Signal-Reception Channels in Spectral Domain Optical Coherence Tomography
      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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    11. Compensation for the Influence of Fluctuations in the Distance to the Object During Noncontact Probing in Spectral Domain Optical Coherence Tomography

      Compensation for the Influence of Fluctuations in the Distance to the Object During Noncontact Probing in Spectral Domain Optical Coherence Tomography
      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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    12. Optical coefficients as tools for increasing the optical coherence tomography contrast for normal brain visualization and glioblastoma detection

      Optical coefficients as tools for increasing the optical coherence tomography contrast for normal brain visualization and glioblastoma detection
      The methods used for digital processing of optical coherence tomography (OCT) and crosspolarization (CP) OCT images are focused on improving the contrast ratio of native structural OCT images. Such advances are particularly important for the intraoperative detection of glioma margins where the visual assessment of OCT images can be difficult and lead to errors. The aim of the study was to investigate the application of optical coefficients obtained from CP ...
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    13. Improving the Transverse Resolution of Optical Coherence Tomography with a Finite Impulse Response Filter and a Series of Numerically Refocused Images

      Improving the Transverse Resolution of Optical Coherence Tomography with a Finite Impulse Response Filter and a Series of Numerically Refocused Images
      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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    14. En-face optical coherence tomography/fluorescence endomicroscopy for minimally invasive imaging using a robotic scanner

      En-face optical coherence tomography/fluorescence endomicroscopy for minimally invasive imaging using a robotic scanner
      We report a compact rigid instrument capable of delivering en-face optical coherence tomography (OCT) images alongside (epi)-fluorescence endomicroscopy (FEM) images by means of a robotic scanning device. Two working imaging channels are included: one for a one-dimensional scanning, forward-viewing OCT probe and another for a fiber bundle used for the FEM system. The robotic scanning system provides the second axis of scanning for the OCT channel while allowing the ...
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    15. Semi-analytical full-wave model for simulations of scans in optical coherence tomography with accounting for beam focusing and the motion of scatterers

      Semi-analytical full-wave model for simulations of scans in optical coherence tomography with accounting for beam focusing and the motion of scatterers
      A full-wave model for simulating images in spectral-domain optical coherence tomography (OCT) with rigorous accounting for the beam-focusing effects is developed. Due to the analytical description of beam focusing, the model is computationally rather efficient. It also uses a rigorous numerical summation of the contributions of the localized sub-resolution scatterers, accounting for variations in the phase-amplitude parameters of the incident and backscattered optical waves, with a subsequent integration of the ...
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  2. About Grigory V. Gelikonov

    Grigory V. Gelikonov

    Grigory V. Gelikonov received his M.S. at the Radiophysical Department of the N.I. Lobachevsky State Nizhny Novgorod University in 1992 and his Ph.D. in 2005.Since 1992 he has been working as a research scientist at the Institute of Applied Physics of the Russian Academy of Science. In 2006 he became Director of BioMedTech Llc. His main scientific interests include the development and creation of single mode fiber elements, invention of new types of fiber couplers, fiber optic Gyro (FOG), and Optical Coherence Tomography (OCT) imaging of biotissues. He has participated in the development of software for automated data acquisition and image processing. Dr. Gelikonov invented a brand new fast in-depth scanning (Russian and US patents) OCT system, a micro lateral scanning probe for endoscopic OCT, and a number of modifications of the OCT technique, including cross-polarization OCT and two-wavelength OCT. Dr. Gelikonov received the State Prize of the Russian Federation in Science and Technology in 1999.