1. Articles from Sangmin Kim

    1-5 of 5
    1. Vector of motion measurements in the living cochlea using a 3D OCT vibrometry system

      Vector of motion measurements in the living cochlea using a 3D OCT vibrometry system

      Optical coherence tomography (OCT) has become an important tool for measuring the vibratory response of the living cochlea. It stands alone in its capacity to measure the intricate motion of the hearing organ through the surrounding otic capsule bone. Nevertheless, as an extension of phase-sensitive OCT, it is only capable of measuring motion along the optical axis. Hence, measurements are 1-D. To overcome this limitation and provide a measure of the 3-D vector of motion in the cochlea, we developed an OCT system with three sample arms in a single interferometer. Taking advantage of the long coherence length of our ...

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    2. Noise and sensitivity in optical coherence tomography based vibrometry

      Noise and sensitivity in optical coherence tomography based vibrometry

      There is growing interest in using the exquisite phase sensitivity of optical coherence tomography (OCT) to measure the vibratory response in organ systems such as the middle and inner ear. Using frequency domain analysis, it is possible to achieve picometer sensitivity to vibration over a wide frequency band. Here we explore the limits of the frequency domain vibratory sensitivity due to additive noise and consider the implication of phase noise statistics on the estimation of vibratory amplitude and phase. Noise statistics are derived in both the Rayleigh ( s/n = 0 ) and Normal distribution ( s/n > 3 ) limits. These theoretical findings ...

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    3. Picometer scale vibrometry in the human middle ear using a surgical microscope based optical coherence tomography and vibrometry system

      Picometer scale vibrometry in the human middle ear using a surgical microscope based optical coherence tomography and vibrometry system

      We have developed a highly phase stable optical coherence tomography and vibrometry system that attaches directly to the accessory area of a surgical microscope common to both the otology clinic and operating room. Careful attention to minimizing sources of phase noise has enabled a system capable of measuring vibrations of the middle ear with a sensitivity of < 5 pm in an awake human patient. The system is shown to be capable of collecting a wide range of information on the morphology and function of the ear in live subjects, including frequency tuning curves below the hearing threshold, maps of tympanic ...

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    4. Endoscopic optical coherence tomography enables morphological and subnanometer vibratory imaging of the porcine cochlea through the round window

      Endoscopic optical coherence tomography enables morphological and subnanometer vibratory imaging of the porcine cochlea through the round window

      A highly phase stable hand-held (HH) endoscopic system has been developed for optical coherence tomography and vibrometry. Designed to transit the ear canal to the middle ear space and peer through the round window (RW), it is capable of imaging the vibratory function of the cochlear soft tissues with subnanometer scale sensitivity. A side-looking, 9 cm long rigid endoscope with a distal diameter of 1.2 mm, was able to fit within the RW niche and provide imaging access. The phase stability was achieved in part by fully integrating a Michelson interferometer into the HH device. Ex vivo imaging of ...

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    5. High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography

      High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography

      Swept-laser sources offer a number of advantages for Phase-sensitive Optical Coherence Tomography (PhOCT). However, inter- and intra-sweep variability leads to calibration errors that adversely affect phase sensitivity. While there are several approaches to overcoming this problem, our preferred method is to simply calibrate every sweep of the laser. This approach offers high accuracy and phase stability at the expense of a substantial processing burden. In this approach, the Hilbert phase of the interferogram from a reference interferometer provides the instantaneous wavenumber of the laser, but is computationally expensive. Fortunately, the Hilbert transform may be approximated by a Finite Impulse-Response (FIR ...

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    1-5 of 5
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  2. Topics in the News

    1. (5 articles) Texas A&M University
    2. (4 articles) UCLA
    3. (1 articles) University of Southern California
    4. (1 articles) Stanford University
    5. (1 articles) Northwestern University
    6. (1 articles) Jikei University School of Medicine
    7. (1 articles) Indiana University
    8. (1 articles) University of Utah
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    High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography Endoscopic optical coherence tomography enables morphological and subnanometer vibratory imaging of the porcine cochlea through the round window Picometer scale vibrometry in the human middle ear using a surgical microscope based optical coherence tomography and vibrometry system Noise and sensitivity in optical coherence tomography based vibrometry Vector of motion measurements in the living cochlea using a 3D OCT vibrometry system PREcise Percutaneous Coronary Intervention for Stent OptimizatION in Treatment of COMPLEX Lesion (PRECISION-COMPLEX) Real-Time Risk Score for Glaucoma Mass Screening by Spectral Domain Optical Coherence Tomography: Development and Validation Macrophages in close proximity to the vitreoretinal interface are potential biomarkers of inflammation during retinal vascular disease Vertical scan imaging of Anterior Segment Optical Coherence Tomography for descemet anchoring caterpillar seta: A case report and review of literature Evaluation of signal degradation due to birefringence in a multiple reference optical coherence tomography system with polarization-based balanced detection An improved method for murine laser-induced choroidal neovascularization lesion quantification from optical coherence tomography images Multimodal Imaging Including Swept Source Optical Coherence Tomography Angiography in A Case with Sclerochoroidal Calcification