1. Articles from Kinpui Chan

    1-15 of 15
    1. Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging

      Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging

      BACKGROUND AND OBJECTIVE: To demonstrate the feasibility of retinal and anterior segment intraoperative widefield imaging using an ultrahigh-speed, swept-source optical coherence tomography (SS-OCT) surgical microscope attachment. PATIENTS AND METHODS: A prototype post-objective SS-OCT using a 1,050-nm wavelength, 400 kHz A-scan rate, vertical cavity surface-emitting laser (VCSEL) light source was integrated to a commercial ophthalmic surgical microscope after the objective. Each widefield OCT data set was acquired in 3 seconds (1,000 × 1,000 A-scans, 12 × 12 mm 2 for retina and 10 × 10 mm 2 for anterior segment). RESULTS: Intraoperative SS-OCT was performed in 20 eyes of 20 patients ...

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    2. Optical Coherence Tomography in the UK Biobank Study – Rapid Automated Analysis of Retinal Thickness for Large Population-Based Studies

      Optical Coherence Tomography in the UK Biobank Study – Rapid Automated Analysis of Retinal Thickness for Large Population-Based Studies

      Purpose To describe an approach to the use of optical coherence tomography (OCT) imaging in large, population-based studies, including methods for OCT image acquisition, storage, and the remote, rapid, automated analysis of retinal thickness. Methods In UK Biobank, OCT images were acquired between 2009 and 2010 using a commercially available “spectral domain” OCT device (3D OCT-1000, Topcon). Images were obtained using a raster scan protocol, 6 mm x 6 mm in area, and consisting of 128 B-scans. OCT image sets were stored on UK Biobank servers in a central repository, adjacent to high performance computers. Rapid, automated analysis of retinal ...

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    3. Detection Of Missampled Interferograms In Frequency Domain OCT With A K-CLOCK

      Detection Of Missampled Interferograms In Frequency Domain OCT With A K-CLOCK

      Optical coherence tomography light sources can be non-linear and attempts to linearize them can lead to asynchrony between the light source and A-line scans and missampling in the scans causing signal noise. Accordingly, a system and methods are provided herein to detect missampling by obtaining a plurality of interferograms; providing at least two wavenumber reference signals at different wavenumbers, wherein the wavenumber reference signals comprise attenuated or enhanced portions of each of the plurality of interferograms; aligning each of the plurality of interferograms according to one of the at least two wavenumber reference signals; and for each of the plurality ...

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    4. Optical imaging method and optical imaging apparatus using optical coherence tomography

      Optical imaging method and optical imaging apparatus using optical coherence tomography

      An optical imaging method in an embodiment includes: a scanning step to scan each of a plurality of A-lines of an object with a signal light while alternately changing the phase difference between the signal light and a reference light to two preset phase differences; a detection step to detect the interference light of the signal light passing through the A-line and the reference light; and an imaging step to generate a complex interference spectrum based on the detection results of the interference lights corresponding to the plurality of A-lines sequentially obtained in the detection step according to the scanning ...

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    5. Optical imaging method and optical imaging apparatus

      Optical imaging method and optical imaging apparatus

      An optical imaging method is provided that can realize, at low cost, the extension of the imaging depth range. An optical imaging apparatus 400 is an apparatus that forms a tomographic image of an object using FD-OCT, and performs a scanning step, detection step and imaging step. In the scanning step, the object is scanned with a signal light while alternately changing the phase difference between the signal light and a reference light to two preset phase differences. In the detection step, interference light of the signal light passing through the object and the reference light is detected. In the ...

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    6. Optical image measurement device including an interference light generator

      Optical image measurement device including an interference light generator

      An optical image measurement device 1 causes an interference light generator to split a low-coherence light into a signal light and a reference light, and superimposes the signal light propagated through a measured object 5000 and the reference light propagated through the reference mirror 9 to generate an interference light. Two-dimensional photosensor arrays 14 and 15 detect the interference light. A computer 16 forms an image of the measured object 5000 based on the detection result. By inserting the optical fiber bundle 5 into the measured object 5000 to perform a measurement, a tomographic image of a deep tissue of ...

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    7. Automated segmentation of outer retinal layers in macular OCT images of patients with retinitis pigmentosa

      Automated segmentation of outer retinal layers in macular OCT images of patients with retinitis pigmentosa
      To provide a tool for quantifying the effects of retinitis pigmentosa (RP) seen on spectral domain optical coherence tomography images, an automated layer segmentation algorithm was developed. This algorithm, based on dual-gradient information and a shortest path search strategy, delineates the inner limiting membrane and three outer retinal boundaries in optical coherence tomography images from RP patients. In addition, an automated inner segment (IS)/outer segment (OS) contour detection method based on the segmentation results is proposed to quantify the locus of points at which the OS thickness goes to zero in a 3D volume scan. The segmentation algorithm and ...
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    8. Optical image measurement device

      Optical image measurement device
      An optical image measurement device comprises: a light source configured to output a light having low temporal coherence and low spatial coherence; an optical system configured to split the light into a signal light and a reference light and superimpose the signal light having passed through a measured object and the reference light, thereby generating an interference light; a light receiver configured to receive the interference light and output an electric signal; and a forming part configured to form an image of the measured object based on the electric signal, wherein: the light receiver has a light receiving face on ...
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    9. Automated layer segmentation of macular OCT images using dual-scale gradient information

      Automated layer segmentation of macular OCT images using dual-scale gradient information
      A novel automated boundary segmentation algorithm is proposed for fast and reliable quantification of nine intra-retinal boundaries in optical coherence tomography (OCT) images. The algorithm employs a two-step segmentation schema based on gradient information in dual scales, utilizing local and complementary global gradient information simultaneously. A shortest path search is applied to optimize the edge selection. The segmentation algorithm was validated with independent manual segmentation and a reproducibility study. It demonstrates high accuracy and reproducibility in segmenting normal 3D OCT volumes. The execution time is about 16 seconds per volume (480x512x128 voxels). The algorithm shows potential for quantifying images from ...
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    10. Optical image measuring apparatus and optical image measuring method for forming a velocity distribution image expressing a moving velocity distribution of the moving matter

      An optical image measuring apparatus capable of speedily measuring a velocity distribution image of a moving matter. Including a broad-band light source, lenses for increasing a beam diameter, a polarizing plate converting the light beam to linearly porlarized light, and a half mirror, a wavelength plate converting the reference light to circularly polarized light, the half mirror superimposing the signal light whose frequency is partially shifted by the moving matter in the object and the reference light is circularly polarized light to produce superimposed light including interference light, CCDs for receiving different polarized light components of the interference light, and ...
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    11. Optical image measuring apparatus and optical image measuring method

      An apparatus, which includes a light source, a polarizing plate for converting the light beam to linearly polarized light, a half mirror for dividing the light beam into signal light and reference light and superimposing the signal light and the reference light on each other to produce interference light, a wavelength plate for converting the reference light to circularly polarized light, a frequency shifter for shifting a frequency of the reference light, a reference mirror which is moved by a piezoelectric element, a polarization beam splitter for extracting an S-polarized light component and a P-polarized light component from the interference ...
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    12. Optical image measuring apparatus for forming an image of an object to be measured based on interference light

      An optical image measuring apparatus capable of effectively obtaining a direct current component of a heterodyne signal which is composed of background light of interference light is provided. The optical image measuring apparatus includes: an optical interference system in which a light beam from a light source is divided into signal light and reference light by a beam splitter, a frequency of the reference light is shifted by a frequency shifter, and the signal light propagating through an object to be measured and the reference light reflected on a mirror are superimposed on each other by the beam splitter to ...
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    13. Optical image measuring apparatus

      Provided is an optical image measuring apparatus capable of easily changing a scanning interval of an object to be measured in a depth direction with high precision. The apparatus includes an interference optical system for superimposing signal light propagating through the object to be measured on reference light subjected to frequency shift to produce interference light, a reference mirror driving unit for driving a mirror to scan the object to be measured in the depth direction, shutters for sampling interference light beams, CCDs for storing charges for only a predetermined storage time and outputting electrical signals, a control unit for ...
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    14. Optical image transmitting system, optical image transmitting apparatus, optical image receiving apparatus, and optical image transmitting method

      Provided is an optical image transmitting system capable of producing signal light including plural image information and emitting the signal light, and in addition, receiving the signal light and selectively extracting target image information. An optical image transmitting system of the present invention includes an optical image transmitting apparatus (100) for producing plural optical image information beams (S1 to Sn) representing plural optical image information and including light beams of different frequencies, superimposing the plural optical image information beams (S1 to Sn) into signal light (S) and emitting the signal light (S) through free space or an optical waveguide such ...
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    15. Optical interferometer employing multiple detectors to detect spatially distorted wavefront in imaging of scattering media

      There is disclosed an optical measurement device which is based on optical interference and it uses a light beam which is radiated to and transmitted through or reflected by a sample, especially a light scattering medium to optically measure the sample. The amount of signal lights effective for optical heterodyne detection is increased, while speckle noises are averaged out. On an observation plane of a concerned point arranged are plural detector elements. From signals obtained by the respective detector elements, an optical signal of the concerned point is obtained.
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    1-15 of 15
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  2. Topics in the News

    1. (14 articles) Topcon Medical Systems
    2. (2 articles) Columbia University
    3. (2 articles) Donald C. Hood
    4. (2 articles) Ali S. Raza
    5. (1 articles) Oxford University
    6. (1 articles) University of Tokyo
    7. (1 articles) Praveen J. Patel
    8. (1 articles) Paul J. Foster
    9. (1 articles) Masanori Hangai
    10. (1 articles) Pearse A. Keane
    11. (1 articles) Stanford University
    12. (1 articles) University of Lübeck
    13. (1 articles) Peking University
    14. (1 articles) Devers Eye Institute
    15. (1 articles) Chinese Academy of Sciences
    16. (1 articles) UC Riverside
    17. (1 articles) University of Heidelberg
    18. (1 articles) Yalin Zheng
    19. (1 articles) Jeffrey M. Liebmann
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    Automated layer segmentation of macular OCT images using dual-scale gradient information Optical image measurement device Automated segmentation of outer retinal layers in macular OCT images of patients with retinitis pigmentosa Optical image measurement device including an interference light generator Chalcogenide-glass polarization-maintaining photonic crystal fiber for mid-infrared supercontinuum generation Supervised machine learning based multi-task artificial intelligence classification of retinopathies OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness and Minimum Cross-Sectional Area in Healthy Eyes Combined intracoronary assessment and treatment of a patient with coronary plaque rapid progression prior to acute myocardial infarction A case report Quantifying microstructural changes in retinitis pigmentosa using spectral domain – optical coherence tomography Photothermal Optical Coherence Tomography of Anti-Angiogenic Treatment in the Mouse Retina Using Gold Nanorods as Contrast Agents Simple and robust calibration procedure for k-linearization and dispersion compensation in optical coherence tomography Optical coherence tomography in varying aetiologies of renal artery stenosis: a case series