1. Articles from Beop-Min Kim

    1-13 of 13
    1. Full ocular biometry through dual-depth whole-eye optical coherence tomography

      Full ocular biometry through dual-depth whole-eye optical coherence tomography

      We propose a new method of determining the optical axis (OA), pupillary axis (PA), and visual axis (VA) of the human eye by using dual-depth whole-eye optical coherence tomography (OCT). These axes, as well as the angles “α” between the OA and VA and “κ” between PA and VA, are important in many ophthalmologic applications, especially in refractive surgery. Whole-eye images are reconstructed based on simultaneously acquired images of the anterior segment and retina. The light from a light source is split into two orthogonal polarization components for imaging the anterior segment and retina, respectively. The OA and PA are identified based ...

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      Mentions: Korea University
    2. High-resolution, dual-depth spectral-domain optical coherence tomography with interlaced detection for whole-eye imaging

      High-resolution, dual-depth spectral-domain optical coherence tomography with interlaced detection for whole-eye imaging

      Dual-depth spectral-domain optical coherence tomography (SD-OCT) enables high-resolution in vivo whole-eye imaging. Two orthogonally polarized beams from a source are focused simultaneously on two axial positions of the anterior segment and the retina. For the detector arm, a 1 × 2 ultrafast optical switch sequentially delivers two spectral interference signals to a single spectrometer, which extends the in-air axial depth range up to 9.44 mm. An off-pivot complex conjugate removal technique doubles the depth range for all anterior segment imaging. The graphics-processing-unit-based parallel signal processing algorithm supports fast two- and three-dimensional image displays. The obtained high-resolution anterior and retinal images ...

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    3. Optically deviated focusing method based high-speed SD-OCT for in vivo retinal clinical applications

      Optically deviated focusing method based high-speed SD-OCT for in vivo retinal clinical applications

      The aim of this study is to provide accurately focused, high-resolution in vivo human retinal depth images using an optically deviated focusing method with spectral-domain optical coherence tomography (SD-OCT) system. The proposed method was applied to increase the retinal diagnosing speed of patients with various values of retinal distances (i.e., the distance between the crystalline eye lens and the retina). The increased diagnosing speed was facilitated through an optical modification in the OCT sample arm configuration. Moreover, the optical path length matching process was compensated using the proposed optically deviated focusing method. The developed system was mounted on a ...

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    4. Spectral domain optical coherence tomography with balanced detection using single line-scan camera and optical delay line

      Spectral domain optical coherence tomography with balanced detection using single line-scan camera and optical delay line

      We propose a spectral domain optical coherence tomography (SD-OCT) system that uses a single line-scan detection scheme for balanced detection. Two phase-opposed spectra, generated by two optical fiber couplers, were detected by using a spectrometer with fast optical switching. A 2.69 km optical fiber was introduced to provide a proper time delay to prevent phase errors caused by the difference in measurement time between the two opposing spectra and unstable output voltages for controlling the galvano-scanner. Hence, a phase difference of π was obtained between the spectra over the sample depth without a phase error, which improved sensitivity by approximately ...

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      Mentions: Korea University
    5. Optics for forming a linear beam in optical coherence tomography

      Optics for forming a linear beam in optical coherence tomography

      This invention relates to an optical coherence tomography, in which a light source and an optical linear beam forming system are adopted to obtain two dimensional image of high quality resolution within short time without affection by any mechanical movements. For such purpose, the optical linear beam forming system (20) comprises semicy Under lens (21), convex lens (22) and slit (23) to implement the frequency domain optical coherence tomography. Parallel light beam from the light source is incident on the surface of the semicylinder lens (21), and focal line of the semicylinder lens (21) is located in front of the ...

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    6. Optical Probe And Optical Coherence Tomography Apparatus Including The Same

      Optical Probe And Optical Coherence Tomography Apparatus Including The Same

      An optical probe for irradiating light onto a subject includes an optical path control unit configured to receive light from outside the optical probe, and change a path of the light within the optical probe; an optical path length control element configured to receive the light having the changed path from the optical path control unit, and change an optical path length of the light as the optical path control unit changes the path of the light; and an optical output unit configured to receive the light having the changed optical path length from the optical path length control element ...

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      Mentions: Samsung
    7. Complex artifact suppression using vestigial sideband filter in Fourier-domain optical coherence tomography

      Complex artifact suppression using vestigial sideband filter in Fourier-domain optical coherence tomography

      In order to achieve computationally efficient mirror image rejection during the off-pivot, full-range approach in spectral-domain optical coherence tomography, we used a vestigial sideband (VSB) filter in place of a Hilbert transform. The appropriate choice of the VSB filter parameters enabled almost complete removal of one sideband with much reduced computational load. To determine the optimal filter parameters, we acquired images of the infrared card and analyzed the mirror suppression ratio of the card surface. Comparison between images obtained using the two filters revealed that the computational load is reduced by 52.4 ± 0.17 % when using the VSB filter ...

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    8. Spectral-domain OCT with dual illumination and interlaced detection for simultaneous anterior segment and retina imaging

      Spectral-domain OCT with dual illumination and interlaced detection for simultaneous anterior segment and retina imaging

      We present Fourier-domain/spectral-domain optical coherence tomography (FD/SD-OCT) using a single spectrometer with dual illumination and interlaced detection at 830 nm, which can provide anterior segment and retinal tomograms simultaneously. Two orthogonal polarization components were used so that both parallel and focused beams could simultaneously be made incident on the eye. This configuration with a polarization-separated sample arm enables us to acquire images from the anterior segment and retina effectively with minimum loss of sample information. In the detector arm, a single spectrometer is illuminated via an ultrafast optical switch for interlaced detection. A graphical user interface (GUI) was ...

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      Mentions: Korea University
    9. High-speed spectral domain polarization-sensitive optical coherence tomography using a single camera and an optical switch at 1.3 µm

      We propose high-speed spectral domain polarization-sensitive optical coherence tomography (SD-PS-OCT) using a single camera and a 1×2 optical switch at the 1.3-µm region. The PS-low coherence interferometer used in the system is constructed using free-space optics. The reflected horizontal and vertical polarization light rays are delivered via an optical switch to a single spectrometer by turns. Therefore, our system costs less to build than those that use dual spectrometers, and the processes of timing and triggering are simpler from the viewpoints of both hardware and software. Our SD-PS-OCT has a sensitivity of 101.5 dB, an axial ...

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    10. OPTICAL COHERENCE TOMOGRAPHY (WO 2009/051446)

      OPTICAL COHERENCE TOMOGRAPHY (WO 2009/051446)

      This invention relates to an optical coherence tomography, in which a light source and an optical linear beam forming system are adopted to obtain two dimensional image of high quality resolution within short time without affection by any mechanical movements. For such purpose, the optical linear beam forming system(20) comprises semicy Under lens(21), convex lens(22) and slit(23) to implement the frequency domain optical coherence tomography. Parallel light beam from the light source is incident on the surface of the semicylinder lens(21), and focal line of the semicylinder lens (21) is located in front of the ...

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    11. Quantification of scattering changes using polarization-sensitive optical coherence tomography

      We demonstrate that changes in the degree of polarization (DOP) depend on changes in the scattering coefficient, and they can be quantified by using a polarization-sensitive optical coherence tomography (PS-OCT) system. We test our hypothesis using liquid and solid phantoms made from Intralipid suspensions and gelatin, respectively. We also quantify the DOP changes with depth caused by changes in the concentration of scatterers in the liquid and solid phantoms. It is clearly shown that the DOP change has a linear relationship with the scattering change. In our previous study, we showed that the axial slope of the DOP is different ...

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    12. Second harmonic optical coherence microscopy for functional optical imaging of biological tissues

      Chang-Keun Kim, Sang-Won Lee, Hyun-Woo Jeong et al. We constructed a second-harmonic optical coherence microscope (OCM) that combines confocal microscopy and the second-harmonic optical coherence tomography technique. This microscope provides micron or submicron resolutions in lateral direction along with coherence gating to achieve a reasonably good ... [Proc. SPIE Int. Soc. Opt. Eng. 6850, 68500Q (2008)] published Tue Feb 12, 2008.
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    13. Optical diagnosis of cervical intraepithelialneoplasm (cin) using polarization-sensitive optical coherence tomography

      Sang-Won Lee, Ji-Yeong Yoo, Jin-Ho Kang, Moon-Sik Kang, Soon-Hee Jung, Yosep Chong, Dong-Su Cha, Kyung-Hee Han, Beop-Min KimWe present a polarization-sensitive optical coherence tomography (PS-OCT) technique that can quantify the polarization changes (the degrees of circular polarization, DOCP) caused by the scattering changes induced by cervical intraepithelial neoplasia (CIN). The axial and lateral resolutions of ... [Opt. Express 16, 2709-2719 (2008)]
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    1-13 of 13
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  2. Topics in the News

    1. (7 articles) Korea University
    2. (6 articles) Yonsei University
    3. (3 articles) Samsung
    4. (2 articles) Kyungpook National University
    5. (2 articles) FDA
    6. (2 articles) Perimeter Medical Imaging
    7. (1 articles) University of Minnesota
    8. (1 articles) Johns Hopkins University
    9. (1 articles) University of Heidelberg
    10. (1 articles) L V Prasad Eye Institute
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    OPTICAL COHERENCE TOMOGRAPHY (WO 2009/051446) Spectral-domain OCT with dual illumination and interlaced detection for simultaneous anterior segment and retina imaging Complex artifact suppression using vestigial sideband filter in Fourier-domain optical coherence tomography Optical Probe And Optical Coherence Tomography Apparatus Including The Same Spectral domain optical coherence tomography with balanced detection using single line-scan camera and optical delay line Optically deviated focusing method based high-speed SD-OCT for in vivo retinal clinical applications Clinical Trials Critical for the Evaluation of Advanced Medical Imaging Tools Voxeleron Welcomes Manabu Tokunaga as new Director of Software Accuracy of Diabetic Retinopathy Staging with a Deep Convolutional Neural Network Using Ultra-Wide-Field Fundus Ophthalmoscopy and Optical Coherence Tomography Angiography A longitudinal comparison in cynomolgus macaques of the effect of brimonidine on optic nerve neuropathy using diffusion tensor imaging magnetic resonance imaging and spectral domain optical coherence tomography Design of 1300-nm spectral domain optical coherence tomography angiography system for iris microvascular imaging Perimeter Medical Imaging AI Announces Important Milestone in ATLAS AI Project with Standalone AI Algorithm Achieving Key Performance Metrics