1. Shuichi Makita

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    1. Mentioned In 81 Articles

    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. Full-range ultrahigh-resolution spectral-domain optical coherence tomography in 1.7 µm wavelength region for deep-penetration and high-resolution imaging of turbid tissues

      Full-range ultrahigh-resolution spectral-domain optical coherence tomography in 1.7 µm wavelength region for deep-penetration and high-resolution imaging of turbid tissues
      For the first time, we developed a full-range ultrahigh-resolution (UHR) spectral-domain optical coherence tomography (SD-OCT) technique working in the 1.7 m wavelength region. This technique allowed high-resolution, deep-tissue imaging. By using a supercontinuum source operating at a wavelength of 1.7 m, an axial resolution of 3.6 m in a tissue specimen was achieved. To enhance the imaging depth of UHR-SD-OCT, we performed full-range OCT imaging based on ...
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    9. Investigation of Thermal Effects of Photocoagulation on Retinal Tissue Using Fine-Motion-Sensitive Dynamic Optical Coherence Tomography

      Investigation of Thermal Effects of Photocoagulation on Retinal Tissue Using Fine-Motion-Sensitive Dynamic Optical Coherence Tomography
      To enable an objective evaluation of photocoagulation, we characterize thermal tissue changes induced by laser irradiation with different laser parameters using optical coherence tomography (OCT). Spectral-domain OCT with a newly developed image processing method was used to monitor the thermal changes of ex vivo porcine retina. A sequence of OCT B-scans was obtained at the same retinal position simultaneously with the photocoagulation. Cross-sectional tissue displacement maps with respect to an ...
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    10. Eye motion corrected OCT imaging with Lissajous scan pattern

      Eye motion corrected OCT imaging with Lissajous scan pattern
      Ophthalmic optical coherence tomography (OCT) is a powerful tool which provides high resolution three dimensional (3D) volumetric image of human retina. However, the measurement data of OCT suffer motion artifact due to the involuntary eye motion during data acquisition. To eliminate this motion artifact and provide the true shape of retinal image, an eye motion corrected OCT imaging method based on Lissajous scan pattern is proposed in this paper. In ...
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    11. Quantitative optical coherence tomography by maximum a-posteriori estimation of signal intensity

      Quantitative optical coherence tomography by maximum a-posteriori estimation of signal intensity
      A maximum a-posteriori (MAP) estimator for signal amplitude of optical coherence tomography (OCT) is presented. This estimator provides an accurate and low bias estimation of the correct OCT signal amplitude even at very low signal-tonoise ratios. As a result, contrast improvement of retinal OCT images is demonstrated. In addition, this estimation method allows for an estimation reliability to be calculated. By combining the MAP estimator with a previously demonstrated attenuation ...
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    12. Noise-immune complex correlation for vasculature imaging based on standard and Jones-matrix optical coherence tomography

      Noise-immune complex correlation for vasculature imaging based on standard and Jones-matrix optical coherence tomography
      A new optical coherence angiography (OCA) method, called correlation mapping OCA (cmOCA), is presented by using the SNR-corrected complex correlation. An SNR-correction theory for the complex correlation calculation is presented. The method also integrates a motion-artifact-removal method for the sample motion induced decorrelation artifact. The theory is further extended to compute more reliable correlation by using multi- channel OCT systems, such as Jones-matrix OCT. The high contrast vasculature imaging of ...
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    13. Quantitative polarization and flow evaluation of choroid and sclera by multifunctional Jones matrix optical coherence tomography

      Quantitative polarization and flow evaluation of choroid and sclera by multifunctional Jones matrix optical coherence tomography
      Quantitative evaluation of optical properties of choroid and sclera are performed by multifunctional optical coherence tomography. Five normal eyes, five glaucoma eyes and one choroidal atrophy eye are examined. The refractive error was found to be correlated with choroidal birefringence, polarization uniformity, and flow in addition to scleral birefringence among normal eyes. The significant differences were observed between the normal and the glaucoma eyes, as for choroidal polarization uniformity, flow ...
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    14. Three-dimensional multifunctional optical coherence tomography for skin imaging

      Three-dimensional multifunctional optical coherence tomography for skin imaging
      Optical coherence tomography (OCT) visualizes cross-sectional microstructures of biological tissues. Recent developments of multifunctional OCT (MF-OCT) provides multiple optical contrasts which can reveal currently unknown tissue properties. In this contribution we demonstrate multifunctional OCT specially designed for dermatological investigation. And by utilizing it to measure four different body parts of in vivo human skin, three-dimensional scattering OCT, OCT angiography, polarization uniformity tomography, and local birefringence tomography images were obtained by ...
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    15. Maximum a posteriori estimator for high-contrast image composition of optical coherence tomography

      Maximum a posteriori estimator for high-contrast image composition of optical coherence tomography
      A quantitative signal amplitude estimator for optical coherence tomography (OCT) is presented. It is based on a statistical model of OCT signal and noise, using a Bayesian maximum a posteriori (MAP) estimation framework. Multiple OCT images are used for estimation, similar to the widely utilized intensity averaging method. The estimator is less biased especially at low-intensity regions, where intensity averaging approaches the noise power and hence is biased. The estimator ...
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    16. Birefringence imaging of posterior eye by multi-functional Jones matrix optical coherence tomography

      Birefringence imaging of posterior eye by multi-functional Jones matrix optical coherence tomography
      A clinical grade prototype of posterior multifunctional Jones matrix optical coherence tomography (JM-OCT) is presented. This JM-OCT visualized depth-localized birefringence in addition to conventional cumulative phase retardation imaging through local Jones matrix analysis. In addition, it simultaneously provides a sensitivity enhanced scattering OCT, a quantitative polarization uniformity contrast, and OCT-based angiography. The probe beam is at 1- m wavelength band. The measurement speed and the depth-resolution were 100,000 A-lines ...
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    17. 1-15 of 81 1 2 3 4 5 6 »
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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.