1. University of Tsukuba

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    1. Mentioned In 151 Articles

    2. Optical coherence tomography apparatus for selectively visualizing and analyzing vascular network of choroidal layer, and image-processing program and image-processing method for the same

      Explore uspto.gov Ophthalmology , Patents
      Optical coherence tomography apparatus for selectively visualizing and analyzing vascular network of choroidal layer, and image-processing program and image-processing method for the same
      From OCT-measured data, only the image data of the choroidal vascular network present in the layer of the choroidal layer is selectively extracted, thereby accurately obtaining the thickness of the choroidal vessels and thickness of the choroidal vascular network from the image data, to allow for quantitative evaluation of the choroidal vascular network. The optical coherence tomography apparatus has an optical coherence tomography device, and a computer that processes the ...
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      Mentions: Yoshiaki Yasuno University of Tsukuba

    3. Clinical prototype of pigment and flow imaging optical coherence tomography for posterior eye investigation

      Explore OSA | OSA Publishing
      Clinical prototype of pigment and flow imaging optical coherence tomography for posterior eye investigation
      Measurements of the randomness of polarization (RP) obtained using polarization-sensitive optical coherence tomography (PS-OCT) are applied in several applications, and RP is attractive for posterior eye imaging. The addition of RP without retardation requires a minimal extension to standard OCT; therefore, we developed a prototype OCT system with a simplified scheme for RP measurement. A compact polarization-diversity receiver module is the only required hardware extension to a standard OCT system ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno University of Tsukuba

    4. Machine-learning based segmentation of the optic nerve head using multi-contrast Jones matrix optical coherence tomography with semi-automatic training dataset generation

      Explore OSA | OSA Publishing
      Machine-learning based segmentation of the optic nerve head using multi-contrast Jones matrix optical coherence tomography with semi-automatic training dataset generation
      A pixel-by-pixel tissue classification framework using multiple contrasts obtained by Jones matrix optical coherence tomography (JM-OCT) is demonstrated. The JM-OCT is an extension of OCT that provides OCT, OCT angiography, birefringence tomography, degree-of-polarization uniformity tomography, and attenuation coefficient tomography, simultaneously. The classification framework consists of feature engineering, k -means clustering that generates a training dataset, training of a tissue classifier using the generated training dataset, and tissue classification by the ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno University of Tsukuba

    5. Pixel-wise segmentation of severely pathologic retinal pigment epithelium and choroidal stroma using multi-contrast Jones matrix optical coherence tomography

      Explore OSA | OSA Publishing Ophthalmology
      Pixel-wise segmentation of severely pathologic retinal pigment epithelium and choroidal stroma using multi-contrast Jones matrix optical coherence tomography
      Tissue segmentation of retinal optical coherence tomography (OCT) is widely used in ophthalmic diagnosis. However, its performance in severe pathologic cases is still insufficient. We propose a pixel-wise segmentation method that uses the multi-contrast measurement capability of Jones matrix OCT (JM-OCT). This method is applicable to both normal and pathologic retinal pigment epithelium (RPE) and choroidal stroma. In this method, features, which are sensitive to specific tissues of interest, are ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno Masahiro Miura

    6. Comparison of intensity, phase retardation, and local birefringence images for filtering blebs using polarization-sensitive optical coherence tomography

      Explore Nature Publishing Group
      Comparison of intensity, phase retardation, and local birefringence images for filtering blebs using polarization-sensitive optical coherence tomography
      Polarization-sensitive optical coherence tomography (PS-OCT) allows the recording of depth-resolved polarimetric measurements. It has been reported that phase retardation and local birefringence images can noninvasively detect fibrotic area in blebs after glaucoma surgery. Evaluation of scar fibrosis in blebs is important not only for predicting bleb function, but also for planning revision trabeculectomy. Herein, we characterize the intensity, phase retardation, and local birefringence images of blebs using PS-OCT. A total ...
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      Mentions: Yoshiaki Yasuno University of Tsukuba Deepa K. Kasaragod

    7. Simultaneous tissue birefringence and deformation measurement by polarization sensitive optical coherence elastography with active compression

      Explore SPIE Digital Library
      Simultaneous tissue birefringence and deformation measurement by polarization sensitive optical coherence elastography with active compression
      Polarization sensitive optical coherence tomography (PS-OCT) measures tissue birefringence, while optical coherence elastography (OCE) reveals the mechanical property of the tissue. Since both birefringence and mechanical properties are associated with tissue microstructures such as collagen, simultaneous PS-OCT and OCE measurement will provide useful insight for the tissue microstructures. In this paper, we present a combined PS-OCT and OCE technique. The PS-OCT is based on Jones matrix OCT theory. It measures ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno University of Tsukuba

    8. Objective evaluation of choroidal melanin contents with polarization-sensitive optical coherence tomography

      Explore SPIE Digital Library Ophthalmology
      Objective evaluation of choroidal melanin contents with polarization-sensitive optical coherence tomography
      We non-invasively evaluated choroidal melanin contents in human eyes with PS-OCT. We calculated the percentage area of low DOPU in the choroidal interstitial stroma for Vogt-Koyanagi- Harada disease with sunset glow fundus, without sunset glow fundus, control group and tessellated fundus with high myopia. The mean percentage area of low DOPU in the sunset group was significantly lower than the other groups. PS-OCT provides an in vivo objective evaluation of ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno Masahiro Miura

    9. Eye-motion-corrected optical coherence tomography angiography using Lissajous scanning

      Explore OSA | OSA Publishing
      Eye-motion-corrected optical coherence tomography angiography using Lissajous scanning
      To correct eye motion artifacts in en face optical coherence tomography angiography (OCT-A) images, a Lissajous scanning method with subsequent software-based motion correction is proposed. The standard Lissajous scanning pattern is modified to be compatible with OCT-A and a corresponding motion correction algorithm is designed. The effectiveness of our method was demonstrated by comparing en face OCT-A images with and without motion correction. The method was further validated by comparing ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno University of Tsukuba

    10. Generation and optimization of superpixels as image processing kernels for Jones matrix optical coherence tomography

      Explore OSA | OSA Publishing
      Generation and optimization of superpixels as image processing kernels for Jones matrix optical coherence tomography
      Jones matrix-based polarization sensitive optical coherence tomography (JM-OCT) simultaneously measures optical intensity, birefringence, degree of polarization uniformity, and OCT angiography. The statistics of the optical features in a local region, such as the local mean of the OCT intensity, are frequently used for image processing and the quantitative analysis of JM-OCT. Conventionally, local statistics have been computed with fixed-size rectangular kernels. However, this results in a trade-off between image sharpness ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno University of Tsukuba

    11. Introduction to the feature issue on the 25 year anniversary of optical coherence tomography

      Explore OSA | OSA Publishing
      Introduction to the feature issue on the 25 year anniversary of optical coherence tomography
      This feature issue commemorates the approximately 25 year history of Optical Coherence Tomography (OCT), one of the most successful biophotonic technologies. While OCT has technological origins traceable to ultrafast laser development and fiber optic system test instrumentation of the 1980s, innovations in low coherence interferometry for optical ranging and imaging for biomedical applications in the U.S., Europe and Japan by the early 1990s led to coinage of the now ...
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      Mentions: Brett E. Bouma Johannes F. de Boer Joseph A. Izatt

    12. Multi-contrast imaging of human posterior eye by Jones matrix optical coherence tomography

      Explore Conference Proceedings
      Multi-contrast imaging of human posterior eye by Jones matrix optical coherence tomography
      A multi-contrast imaging of pathologic posterior eyes is demonstrated by Jones matrix optical coherence tomography (Jones matrix OCT). The Jones matrix OCT provides five tomographies, which includes scattering, local attenuation, birefringence, polarization uniformity, and optical coherence angiography, by a single scan. The hardware configuration, algorithms of the Jones matrix OCT as well as its application to ophthalmology is discussed.
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      Mentions: Yoshiaki Yasuno University of Tsukuba

    13. Noise-bias and polarization-artifact corrected optical coherence tomography by maximum a-posteriori intensity estimation

      Explore OSA | OSA Publishing Ophthalmology
      Noise-bias and polarization-artifact corrected optical coherence tomography by maximum a-posteriori intensity estimation
      We propose using maximum a-posteriori (MAP) estimation to improve the image signal-to-noise ratio (SNR) in polarization diversity (PD) optical coherence tomography. PD-detection removes polarization artifacts, which are common when imaging highly birefringent tissue or when using a flexible fiber catheter. However, dividing the probe power to two polarization detection channels inevitably reduces the SNR. Applying MAP estimation to PD-OCT allows for the removal of polarization artifacts while maintaining and improving ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno Masahiro Miura

    14. Three-dimensional eye motion correction by Lissajous scan optical coherence tomography

      Explore OSA | OSA Publishing Ophthalmology
      Three-dimensional eye motion correction by Lissajous scan optical coherence tomography
      A three-dimensional optical coherence tomography imaging method based on Lissajous scanning is presented. This method was designed to correct eye motion in OCT images. A Lissajous scanning pattern, which has a trajectory that frequently overlaps with itself, is adopted as the OCT scanning protocol to obtain measurement data. Eye motion artifacts are then corrected automatically by software. By comparing the images without and with motion correction, we show the effectiveness ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno University of Tsukuba

    15. Polarization sensitive optical coherence tomography – a review [Invited]

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      Polarization sensitive optical coherence tomography – a review [Invited]
      Optical coherence tomography (OCT) is now a well-established modality for high-resolution cross-sectional and three-dimensional imaging of transparent and translucent samples and tissues. Conventional, intensity based OCT, however, does not provide a tissue-specific contrast, causing an ambiguity with image interpretation in several cases. Polarization sensitive (PS) OCT draws advantage from the fact that several materials and tissues can change the lights polarization state, adding an additional contrast channel and providing quantitative ...
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      Mentions: Johannes F. de Boer Christoph K. Hitzenberger Yoshiaki Yasuno

    16. High contrast and polarization-artifact-free optical coherence tomography by maximum a-posteriori estimation

      Explore Conference Proceedings
      High contrast and polarization-artifact-free optical coherence tomography by maximum a-posteriori estimation
      We propose a maximum a-posteriori (MAP) intensity estimator to improve the image contrast of polarization diversity (PD)-OCT imaging to achieve high contrast polarization-artifact-free images. The MAP estimator compensates for the inevitable reduction of signal-to-noise ratio (SNR) in PD-OCT caused by the splitting of power into two polarization detection channels. It also has low noise-offset in low intensity regions such as the vitreous. This method is applied to posterior eye ...
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      Mentions: Shuichi Makita Yoshiaki Yasuno Masahiro Miura
    17. 1-15 of 151 1 2 3 4 5 6 7 8 9 10 »
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  4. About University of Tsukuba

    University of Tsukuba

    University of Tsukuba is located in the city of Tsukuba. The university is ranked one of the top Asian universities in the "Academic Ranking of World Universities" and is ranked 102-150 in the world. The University of Tsukuba has had several Nobel Prize winners so far, namely Leo Esaki, Hideki Shirakawa and Sin-Itiro Tomonaga, which is extremely rare among universities in Asia, where there have been fewer Nobel laureates than in European and American universities. 

    The Computational Optics Group (COG)  at the University of Tsukuba formed in 1999 as a division of applied optics laboratory, institute of applied physics, university of Tsukuba. On that moment we were not COG but spatio-temporal optics group, and our main research subject was spatio-temporal optical computing.   In 2000, we started a optical measurement project using spatio-temporal optical computing technologies, and in 2002, we changed our direction to more computationally.   Since 2002, our main research interest is computer assisted optical measurment. We are trying to introduce computational technologies into optical measurement.  Since 2007, we are an independent research group and no longer a part of Applied Optics Laboratory of University of Tsukuba.

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