1. Shuichi Makita

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    1. Mentioned In 90 Articles

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

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

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

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

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

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

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

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

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

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

      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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    12. Birefringence and vascular imaging of in vivo human skin by Jones-matrix optical coherence tomography

      Birefringence and vascular imaging of in vivo human skin by Jones-matrix optical coherence tomography
      A customized 1310-nm Jones-matrix optical coherence tomography (JM-OCT) for dermatological investigation was constructed and used for in vivo normal human skin tissue imaging. This system can simultaneously measure the threedimensional depth-resolved local birefringence, complex-correlation based OCT angiography (OCT-A), degree-ofpolarization- uniformity (DOPU) and scattering OCT intensity. By obtaining these optical properties of tissue, the morphology, vasculature, and collagen content of skin can be deduced and visualized. Structures in the deep layers ...
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    13. Motion-corrected en face optical coherence tomography angiography imaging based on the modified Lissajous scanning pattern

      Motion-corrected en face optical coherence tomography angiography imaging based on the modified Lissajous scanning pattern
      A motion - corrected en face optical coherence tomography angiography (OCT - A) imaging method is presented in this paper. This method was designed to correct eye motion artifacts in en face OCT - A images automatically using a software. A modified Lissajous scanning pattern, which is compatible with OCT - A, was adopted as the scanning protocol for the optical coherence tomography (OCT) machine to obtain the OCT - A data. The OCT - A ...
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    14. Evaluation of intraretinal migration of retinal pigment epithelial cells with Jones matrix optical coherence tomography

      Evaluation of intraretinal migration of retinal pigment epithelial cells with Jones matrix optical coherence tomography
      We evaluated intraretinal RPE migration in AMD using multimodal imaging including polarimetric images. Depolarized light images were computed using a PS-SLO. M-DOPU was calculated using multifunctional Jones-matrix OCT. RPE migration was detected in 59 of 155 eyes. Focal similarities could be confirmed among en-face projection images of minimum M-DOPU, depolarized light images, and NIR-AF images.
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    15. Three-dimensional multi-contrast imaging of in vivo human skin by Jones matrix optical coherence tomography

      Three-dimensional multi-contrast imaging of in vivo human skin by Jones matrix optical coherence tomography
      A custom made dermatological Jones matrix optical coherence tomography (JM-OCT) is presented. It uses a passive-polarization-delay component based swept-source JM-OCT configuration, but is specially designed for in vivo human skin measurement. The center wavelength of its probe beam is 1310 nm and the A-line rate is 49.6 kHz. The JM-OCT is capable of simultaneously providing birefringence (local retardation) tomography, degree-of-polarization-uniformity tomography, complex-correlation-based optical coherence angiography, and conventional scattering OCT ...
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    16. Noise stochastic corrected maximum a posteriori estimator for birefringence imaging using polarization-sensitive optical coherence tomography

      Noise stochastic corrected maximum a posteriori estimator for birefringence imaging using polarization-sensitive optical coherence tomography
      This paper presents a noise-stochastic corrected maximum a posteriori estimator for birefringence imaging using Jones matrix optical coherence tomography. The estimator described in this paper is based on the relationship between probability distribution functions of the measured birefringence and the effective signal to noise ratio (ESNR) as well as the true birefringence and the true ESNR. The Monte Carlo method is used to numerically describe this relationship and adaptive 2D ...
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  2. About Shuichi Makita

    Shuichi Makita is a Researcher in the Computational Optics Group in the Institute of Applied Physics, University of Tsukuba in Japan.