1. Articles from Zhenguo Wang

    1-11 of 11
    1. 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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    2. OCT angiography calculation with optimized signal processing

      OCT angiography calculation with optimized signal processing

      Methods and systems for angiographic imaging with optical coherence tomography (OCT) are described using ratio-based and angiographic deviation based calculations. In using these calculations to determine motion, arbitrary interframe permutations may be used, post-calculated, non-linear results for projection visualization may be averaged, poor matches may be eliminated on an A-line by A-line basis, windowing functions may be used to improve results, partial spectrums may be used when capturing data, and a minimum intensity threshold may be used for determining which pixels to use.

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    3. Optical imaging apparatus, optical imaging method, apparatus for setting characteristics of a light source, and method for setting characteristics of a light source

      Optical imaging apparatus, optical imaging method, apparatus for setting characteristics of a light source, and method for setting characteristics of a light source

      An embodiment provides a method for setting the characteristics of the light to be output from a light source unit for optical coherence tomography, using a computer. This method is performed by using relation information in which a representative wavelength, a wavelength range including said representative wavelength, and the light loss amount due to absorption by a medium are related to each other. This method includes the following steps: setting each value of a first parameter and a second parameter among the representative wavelength, the wavelength range, and the light loss amount; acquiring a value of a third parameter among ...

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    4. 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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    5. 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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    6. 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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    7. 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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    8. High-resolution imaging diagnosis and staging of bladder cancer: comparison between optical coherence tomography and high-frequency ultrasound

      Zhijia Yuan, Zhenguo Wang, Rubin Pan et al. A comparative study between 1.3-[mu]m optical coherence tomography (OCT) and 40-MHz high-frequency ultrasound (HFUS) is presented to enhance imaging of bladder cancers ex vivo. A standard rat bladder cancer model in which transitional cell carcinoma (TCC) was induced by intravesical instillation of ... [J. Biomed. Opt. 13, 054007 (2008)] published Fri Sep 12, 2008.
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    9. Optical coherence Doppler tomography quantifies laser speckle contrast imaging for blood flow imaging in the rat cerebral cortex

      Optical coherence Doppler tomography quantifies laser speckle contrast imaging for blood flow imaging in the rat cerebral cortex

      A dual-imaging modality is demonstrated for high-resolution quantitative imaging of local cerebral blood flow in the rat cortex by combining simultaneous spectral-domain Doppler optical coherence tomography (SDOCT) and full-field laser speckle contrast imaging (LSCI). Preliminary studies in tissue flow phantom and cocaine-induced cerebral blood flow changes indicated that by correlating coregistered cortical arterial blood flow, the relative measurement of flow changes by LSCI could be accurately calibrated by the absolute flow imaging provided by SDOCT (least square fit, r2≈0.96). Quantitative LSCI of cerebral blood flow is crucial to the quantitative analyses of the spatiotemporal hemodynamics of functional brain ...

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    10. Assessment of Dermal Wound Repair after Collagen Implantation with Optical Coherence Tomography

      We present an animal study to examine the utility and potential limitations of optical coherence tomography (OCT) for noninvasive evaluation of biomaterial scaffold–assisted wound healing. The transverse and axial resolutions of the OCT system at the wavelength of 1.3 μm were 12 and 10 μm, respectively. A murine full-thickness transcutaneous wound model was employed, in which a 10 mm full-thickness wound was created on the back of each male Balb/cJ mouse and a porous collagen scaffold was implanted in the wound bed followed by coverage with a TegadermTM film. Sequential cross-sectional OCT scans were performed at different ...
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    11. Optical Coherence Tomography: A Noninvasive Method to Assess Wound Reepithelialization

      Background Accurate assessment of wound healing may require invasive tissue biopsies, limiting its clinical usefulness in humans. Optical coherence tomography (OCT) is a novel, high-resolution method using light reflection to obtain noninvasive cross sectional imaging of biological tissues. ObjectivesTo evaluate the utility of OCT for assessing wound reepithelialization in a porcine model. MethodsThe authors conducted an animal study with two domestic pigs. Excisional cutaneous wounds were created over the ventral surface of the animals using an electric dermatome set at a depth of 600 μm. The wounds were excised two or three days later and precisely marked to guide initial ...
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    1-11 of 11
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  2. Topics in the News

    1. (7 articles) Topcon Medical Systems
    2. (3 articles) SUNY at Stony Brook
    3. (3 articles) Yingtian Pan
    4. (1 articles) University of Tokyo
    5. (1 articles) Columbia University
    6. (1 articles) Congwu Du
    7. (1 articles) Nagahisa Yoshimura
    8. (1 articles) Masanori Hangai
    9. (1 articles) Donald C. Hood
    10. (1 articles) Topcon 3D OCT-1000
    11. (1 articles) University of Florida
    12. (1 articles) Delft University of Technology
    13. (1 articles) Huikai K. Xie
    14. (1 articles) Xuan Liu
    15. (1 articles) Eduardo Margallo Balbás
    16. (1 articles) Thorlabs
    17. (1 articles) MedLumics
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    Optical coherence Doppler tomography quantifies laser speckle contrast imaging for blood flow imaging in the rat cerebral cortex Automated layer segmentation of macular OCT images using dual-scale gradient information Optical imaging method and optical imaging apparatus Optical imaging method and optical imaging apparatus using optical coherence tomography Detection Of Missampled Interferograms In Frequency Domain OCT With A K-CLOCK Optical imaging apparatus, optical imaging method, apparatus for setting characteristics of a light source, and method for setting characteristics of a light source OCT angiography calculation with optimized signal processing RAG-FW: A hybrid convolutional framework for the automated extraction of retinal lesions and lesion-influenced grading of human retinal pathology Self-aligned micro-optic integrated photonic platform Real-time Lissajous imaging with a low-voltage 2-axis MEMS scanner based on electrothermal actuation Optically computed optical coherence tomography for volumetric imaging In-Vitro MPI-guided IVOCT catheter tracking in real time for motion artifact compensation