The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yoshiaki Yasuno - One of the best experts on this subject based on the ideXlab platform.
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depth resolved investigation of multiple optical properties and wrinkle morphology in eye corner areas with multi contrast Jones Matrix optical coherence tomography
Skin Research and Technology, 2021Co-Authors: Kohei Yamazaki, Shuichi Makita, Yoshiaki Yasuno, Arata Miyazawa, Masaki Kobayashi, Tetsuya Sayo, Yoshito Takahashi, Shingo SakaiAbstract:BACKGROUND Multi-contrast Jones Matrix optical coherence tomography (JM-OCT) can provide quantitative depth-resolved local optical properties by improving the measurement algorithm. MATERIALS AND METHODS We examined the relationship between depth-resolved local optical properties of eye-corner skin measured by JM-OCT and corresponding wrinkle morphology of aged women (n = 21; age range, 71.7 ± 1.7 years). Wrinkle morphology was analyzed by measuring the surface topography of three-dimensional replicas. The same regions were measured three-dimensionally by JM-OCT, and the local optical properties at each depth were computed. RESULTS Birefringence (BR) and mean wrinkle depth correlated significantly at a depth of 88.2-138.6 µm from the skin surface, and attenuation coefficient (AC) and mean wrinkle depth correlated significantly at a depth of 12.6-18.9 µm and 189-459.9 μm from the skin surface, although a degree of polarization uniformity (DOPU) did not. Stepwise multiple regression analysis demonstrated that a significant regression equation (R2 = 0.649, P < .001) for predicting mean wrinkle depth was determined by BR at 107.1 µm depth (BR 107.1 µm ), DOPU at 170.1 µm (DOPU 170.1µm ), and AC at 252 µm (AC 252 µm ) as independent variables and that these standardized beta regression coefficients were -0.860, -0.593, and -0.440, respectively, suggesting that BR, DOPU, and AC sufficiently explained mean wrinkle depth. CONCLUSION These results suggest that BR 107.1 µm , DOPU 170.1 µm, and AC 252 µm may indicate collagen-related structure in the papillary, upper-reticular dermis, and microstructure or tissue density in reticular dermis, respectively, and may be involved in wrinkle formation.
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depth resolved investigation of multiple optical properties and wrinkle morphology in eye corner area by multi functional Jones Matrix optical coherence tomography
Photonics in Dermatology and Plastic Surgery 2020, 2020Co-Authors: Kohei Yamazaki, Shuichi Makita, Yoshiaki Yasuno, Arata Miyazawa, Masaki Kobayashi, Tetsuya Sayo, Yoshito Takahashi, Shingo SakaiAbstract:We examined the relationship between depth-resolved local optical properties of eye-corner skin measured by multifunctional Jones Matrix optical coherence tomography (JM-OCT) and corresponding wrinkle morphology of aged women (n=21; age range, 71.7±1.7). Wrinkle morphology parameters were analyzed by measuring surface topography of three-dimensional silicone replicas. The same regions were measured three-dimensionally by JM-OCT and the means of several optical properties were computed at each depth. Optical properties include birefringence (BR), attenuation coefficient (AC), and degree-of-polarization uniformity (DOPU). BR and AC were correlated with mean wrinkle depth (WD), although DOPU was not. Significant correlations were found between WD and BR at 88.2 to 138.6 μm depth region from the skin surface (highest correlation at 113.4 μm), and between WD and AC at 12.6 to 18.9 μm and 189 to 459.9 μm depth regions from the skin surface (highest correlations at 18.9 μm and 415.8 μm). This suggests that the collagen structure of the papillary dermis and the microstructure and/or tissue density of the upper epidermis and reticular dermis may be associated with wrinkle morphology. Multiple regression analysis was used to examine the highest significant correlations of BR (113.4 μm) and AC (18.9 μm, 415.8 μm). A significant regression coefficient (R2=0.547, p = 0.001) was obtained, indicating that only BR and AC could sufficiently explain WD. Beta coefficients of BR (113.4 μm), AC (18.9 μm), and AC (415.8 μm) were −0.384, −0.369, and −0.354, respectively. This suggests that the upper epidermis, papillary dermis, and reticular dermis may contribute similarly to wrinkle formation.
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clinical Jones Matrix oct for diagnosis of macular disease conference presentation
Ophthalmic Technologies XXIX, 2019Co-Authors: Shinnosuke Azuma, Shuichi Makita, Masahiro Miura, Toshihiro Mino, Tatsuo Yamaguchi, Yoshiaki YasunoAbstract:Jones Matrix optical coherence tomography (JM-OCT) is a functional extension of OCT. However, the clinical utility of JM-OCT is not widely accepted. Because of its hardware complexity and poorly established methods for clinical interpretation. In this study, we propose the approaches to solve the above-mentioned problems. To reduce the hardware complexity, we employ encapsulated passive polarization delay module (PPD) and encapsulated polarization diversity detection module (PDD), and develop full-function JM-OCT and simplified JM-OCT. In addition, we developed a pixel wise segmentation method for JM-OCT. The full-function JM-OCT which uses both PDD and PPD measures OCT, OCT angiography (OCTA), degree-of-polarization-uniformity (DOPU) and birefringence. The simplified JM-OCT which uses only PDD measures OCT, OCTA, and DOPU but not birefringence. In both JM-OCT systems, all the optical components are packed in a standard-sized retinal scanner. A pixel-wise segmentation method for retinal pigment epithelium (RPE) and choroidal stroma exploits multiple types of images obtained by the JM-OCT. Attenuation coefficient, OCTA, and DOPU are combined to synthesize a new artificial contrast. By applying a simple threshold to it, the target tissue is segmented. After segmenting the RPE, an en face “melano-layer thickness map” is created. A Normal subject and a pigment epithelial detachment (PED) subject are obtained by full-function JM-OCT and simplified JM-OCT. In PED subject, thickened RPE, hyper-reflective foci, and damaged RPE are correctly detected by RPE segmentation. In addition, created melano-layer thickness map has similar patterns to infrared fundus autofluorescence (NIR-AF), and it can contribute further interpretation of the NIR-AF.
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Jones Matrix tomography principle implementation and application
Conference on Lasers and Electro-Optics, 2018Co-Authors: Yoshiaki YasunoAbstract:Here we present the basic principle and applications of Jones Matrix optical coherence tomography (JM-OCT), which simultaneously visualizes scattering, polarization, and flow property of living tissue.
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pixel wise segmentation of severely pathologic retinal pigment epithelium and choroidal stroma using multi contrast Jones Matrix optical coherence tomography
Biomedical Optics Express, 2018Co-Authors: Shinnosuke Azuma, Shuichi Makita, Masahiro Miura, Yasushi Ikuno, Arata Miyazawa, Yoshiaki YasunoAbstract: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 synthesized by combining the multi-contrast images of JM-OCT, including attenuation coefficient, degree-of-polarization-uniformity, and OCT angiography. The tissue segmentation is done by simple thresholding of the feature. Compared with conventional segmentation methods for pathologic maculae, the proposed method is less computationally intensive. The segmentation method was validated by applying it to images from normal and severely pathologic cases. The segmentation results enabled the development of several types of en face visualizations, including melano-layer thickness maps, RPE elevation maps, choroidal thickness maps, and choroidal stromal attenuation coefficient maps. These facilitate close examination of macular pathology. The melano-layer thickness map is very similar to a near infrared fundus autofluorescence image, so the map can be used to identify the source of a hyper-autofluorescent signal.
Shuichi Makita - One of the best experts on this subject based on the ideXlab platform.
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depth resolved investigation of multiple optical properties and wrinkle morphology in eye corner areas with multi contrast Jones Matrix optical coherence tomography
Skin Research and Technology, 2021Co-Authors: Kohei Yamazaki, Shuichi Makita, Yoshiaki Yasuno, Arata Miyazawa, Masaki Kobayashi, Tetsuya Sayo, Yoshito Takahashi, Shingo SakaiAbstract:BACKGROUND Multi-contrast Jones Matrix optical coherence tomography (JM-OCT) can provide quantitative depth-resolved local optical properties by improving the measurement algorithm. MATERIALS AND METHODS We examined the relationship between depth-resolved local optical properties of eye-corner skin measured by JM-OCT and corresponding wrinkle morphology of aged women (n = 21; age range, 71.7 ± 1.7 years). Wrinkle morphology was analyzed by measuring the surface topography of three-dimensional replicas. The same regions were measured three-dimensionally by JM-OCT, and the local optical properties at each depth were computed. RESULTS Birefringence (BR) and mean wrinkle depth correlated significantly at a depth of 88.2-138.6 µm from the skin surface, and attenuation coefficient (AC) and mean wrinkle depth correlated significantly at a depth of 12.6-18.9 µm and 189-459.9 μm from the skin surface, although a degree of polarization uniformity (DOPU) did not. Stepwise multiple regression analysis demonstrated that a significant regression equation (R2 = 0.649, P < .001) for predicting mean wrinkle depth was determined by BR at 107.1 µm depth (BR 107.1 µm ), DOPU at 170.1 µm (DOPU 170.1µm ), and AC at 252 µm (AC 252 µm ) as independent variables and that these standardized beta regression coefficients were -0.860, -0.593, and -0.440, respectively, suggesting that BR, DOPU, and AC sufficiently explained mean wrinkle depth. CONCLUSION These results suggest that BR 107.1 µm , DOPU 170.1 µm, and AC 252 µm may indicate collagen-related structure in the papillary, upper-reticular dermis, and microstructure or tissue density in reticular dermis, respectively, and may be involved in wrinkle formation.
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depth resolved investigation of multiple optical properties and wrinkle morphology in eye corner area by multi functional Jones Matrix optical coherence tomography
Photonics in Dermatology and Plastic Surgery 2020, 2020Co-Authors: Kohei Yamazaki, Shuichi Makita, Yoshiaki Yasuno, Arata Miyazawa, Masaki Kobayashi, Tetsuya Sayo, Yoshito Takahashi, Shingo SakaiAbstract:We examined the relationship between depth-resolved local optical properties of eye-corner skin measured by multifunctional Jones Matrix optical coherence tomography (JM-OCT) and corresponding wrinkle morphology of aged women (n=21; age range, 71.7±1.7). Wrinkle morphology parameters were analyzed by measuring surface topography of three-dimensional silicone replicas. The same regions were measured three-dimensionally by JM-OCT and the means of several optical properties were computed at each depth. Optical properties include birefringence (BR), attenuation coefficient (AC), and degree-of-polarization uniformity (DOPU). BR and AC were correlated with mean wrinkle depth (WD), although DOPU was not. Significant correlations were found between WD and BR at 88.2 to 138.6 μm depth region from the skin surface (highest correlation at 113.4 μm), and between WD and AC at 12.6 to 18.9 μm and 189 to 459.9 μm depth regions from the skin surface (highest correlations at 18.9 μm and 415.8 μm). This suggests that the collagen structure of the papillary dermis and the microstructure and/or tissue density of the upper epidermis and reticular dermis may be associated with wrinkle morphology. Multiple regression analysis was used to examine the highest significant correlations of BR (113.4 μm) and AC (18.9 μm, 415.8 μm). A significant regression coefficient (R2=0.547, p = 0.001) was obtained, indicating that only BR and AC could sufficiently explain WD. Beta coefficients of BR (113.4 μm), AC (18.9 μm), and AC (415.8 μm) were −0.384, −0.369, and −0.354, respectively. This suggests that the upper epidermis, papillary dermis, and reticular dermis may contribute similarly to wrinkle formation.
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clinical Jones Matrix oct for diagnosis of macular disease conference presentation
Ophthalmic Technologies XXIX, 2019Co-Authors: Shinnosuke Azuma, Shuichi Makita, Masahiro Miura, Toshihiro Mino, Tatsuo Yamaguchi, Yoshiaki YasunoAbstract:Jones Matrix optical coherence tomography (JM-OCT) is a functional extension of OCT. However, the clinical utility of JM-OCT is not widely accepted. Because of its hardware complexity and poorly established methods for clinical interpretation. In this study, we propose the approaches to solve the above-mentioned problems. To reduce the hardware complexity, we employ encapsulated passive polarization delay module (PPD) and encapsulated polarization diversity detection module (PDD), and develop full-function JM-OCT and simplified JM-OCT. In addition, we developed a pixel wise segmentation method for JM-OCT. The full-function JM-OCT which uses both PDD and PPD measures OCT, OCT angiography (OCTA), degree-of-polarization-uniformity (DOPU) and birefringence. The simplified JM-OCT which uses only PDD measures OCT, OCTA, and DOPU but not birefringence. In both JM-OCT systems, all the optical components are packed in a standard-sized retinal scanner. A pixel-wise segmentation method for retinal pigment epithelium (RPE) and choroidal stroma exploits multiple types of images obtained by the JM-OCT. Attenuation coefficient, OCTA, and DOPU are combined to synthesize a new artificial contrast. By applying a simple threshold to it, the target tissue is segmented. After segmenting the RPE, an en face “melano-layer thickness map” is created. A Normal subject and a pigment epithelial detachment (PED) subject are obtained by full-function JM-OCT and simplified JM-OCT. In PED subject, thickened RPE, hyper-reflective foci, and damaged RPE are correctly detected by RPE segmentation. In addition, created melano-layer thickness map has similar patterns to infrared fundus autofluorescence (NIR-AF), and it can contribute further interpretation of the NIR-AF.
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pixel wise segmentation of severely pathologic retinal pigment epithelium and choroidal stroma using multi contrast Jones Matrix optical coherence tomography
Biomedical Optics Express, 2018Co-Authors: Shinnosuke Azuma, Shuichi Makita, Masahiro Miura, Yasushi Ikuno, Arata Miyazawa, Yoshiaki YasunoAbstract: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 synthesized by combining the multi-contrast images of JM-OCT, including attenuation coefficient, degree-of-polarization-uniformity, and OCT angiography. The tissue segmentation is done by simple thresholding of the feature. Compared with conventional segmentation methods for pathologic maculae, the proposed method is less computationally intensive. The segmentation method was validated by applying it to images from normal and severely pathologic cases. The segmentation results enabled the development of several types of en face visualizations, including melano-layer thickness maps, RPE elevation maps, choroidal thickness maps, and choroidal stromal attenuation coefficient maps. These facilitate close examination of macular pathology. The melano-layer thickness map is very similar to a near infrared fundus autofluorescence image, so the map can be used to identify the source of a hyper-autofluorescent signal.
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machine learning based segmentation of the optic nerve head using multi contrast Jones Matrix optical coherence tomography with semi automatic training dataset generation
Biomedical Optics Express, 2018Co-Authors: Deepa Kasaragod, Shuichi Makita, Youngjoo Hong, Yoshiaki YasunoAbstract: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 trained classifier. The feature engineering process generates synthetic features from the primary optical contrasts obtained by JM-OCT. The tissue classification is performed in the feature space of the engineered features. We applied this framework to the in vivo analysis of optic nerve heads of posterior eyes. This classified each JM-OCT pixel into prelamina, lamina cribrosa (lamina beam), and retrolamina tissues. The lamina beam segmentation results were further utilized for birefringence and attenuation coefficient analysis of lamina beam.
Youngjoo Hong - One of the best experts on this subject based on the ideXlab platform.
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machine learning based segmentation of the optic nerve head using multi contrast Jones Matrix optical coherence tomography with semi automatic training dataset generation
Biomedical Optics Express, 2018Co-Authors: Deepa Kasaragod, Shuichi Makita, Youngjoo Hong, Yoshiaki YasunoAbstract: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 trained classifier. The feature engineering process generates synthetic features from the primary optical contrasts obtained by JM-OCT. The tissue classification is performed in the feature space of the engineered features. We applied this framework to the in vivo analysis of optic nerve heads of posterior eyes. This classified each JM-OCT pixel into prelamina, lamina cribrosa (lamina beam), and retrolamina tissues. The lamina beam segmentation results were further utilized for birefringence and attenuation coefficient analysis of lamina beam.
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generation and optimization of superpixels as image processing kernels for Jones Matrix optical coherence tomography
Biomedical Optics Express, 2017Co-Authors: Arata Miyazawa, Shuichi Makita, Youngjoo Hong, Deepa Kasaragod, Yoshiaki YasunoAbstract: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 and statistical accuracy. We introduce a superpixel method to JM-OCT for generating the flexible kernels of local statistics. A superpixel is a cluster of image pixels that is formed by the pixels’ spatial and signal value proximities. An algorithm for superpixel generation specialized for JM-OCT and its optimization methods are presented in this paper. The spatial proximity is in two-dimensional cross-sectional space and the signal values are the four optical features. Hence, the superpixel method is a six-dimensional clustering technique for JM-OCT pixels. The performance of the JM-OCT superpixels and its optimization methods are evaluated in detail using JM-OCT datasets of posterior eyes. The superpixels were found to well preserve tissue structures, such as layer structures, sclera, vessels, and retinal pigment epithelium. And hence, they are more suitable for local statistics kernels than conventional uniform rectangular kernels.
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three dimensional multi contrast imaging of in vivo human skin by Jones Matrix optical coherence tomography
Biomedical Optics Express, 2017Co-Authors: Shuichi Makita, Youngjoo Hong, Deepa Kasaragod, Yoshiaki YasunoAbstract: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. To evaluate the performance of this JM-OCT, we measured in vivo human skin at several locations. Using the four kinds of OCT contrasts, the morphological characteristics and optical properties of different skin types were visualized.
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birefringence and vascular imaging of in vivo human skin by Jones Matrix optical coherence tomography
Proceedings of SPIE, 2017Co-Authors: Shuichi Makita, Youngjoo Hong, Deepa Kasaragod, Yoshiaki YasunoAbstract: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 of the epithelium were observed with depth-resolved local birefringence and polarization uniformity images. These results suggest high diagnostic and investigative potential of JM-OCT for dermatology.
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optimization method of superpixel analysis for multi contrast Jones Matrix tomography conference presentation
Proceedings of SPIE, 2017Co-Authors: Arata Miyazawa, Shuichi Makita, Youngjoo Hong, Masahiro Miura, Deepa Kasaragod, Yoshiaki YasunoAbstract:Local statistics are widely utilized for quantification and image processing of OCT. For example, local mean is used to reduce speckle, local variation of polarization state (degree-of-polarization-uniformity (DOPU)) is used to visualize melanin. Conventionally, these statistics are calculated in a rectangle kernel whose size is uniform over the image. However, the fixed size and shape of the kernel result in a tradeoff between image sharpness and statistical accuracy. Superpixel is a cluster of pixels which is generated by grouping image pixels based on the spatial proximity and similarity of signal values. Superpixels have variant size and flexible shapes which preserve the tissue structure. Here we demonstrate a new superpixel method which is tailored for multifunctional Jones Matrix OCT (JM-OCT). This new method forms the superpixels by clustering image pixels in a 6-dimensional (6-D) feature space (spatial two dimensions and four dimensions of optical features). All image pixels were clustered based on their spatial proximity and optical feature similarity. The optical features are scattering, OCT-A, birefringence and DOPU. The method is applied to retinal OCT. Generated superpixels preserve the tissue structures such as retinal layers, sclera, vessels, and retinal pigment epithelium. Hence, superpixel can be utilized as a local statistics kernel which would be more suitable than a uniform rectangle kernel. Superpixelized image also can be used for further image processing and analysis. Since it reduces the number of pixels to be analyzed, it reduce the computational cost of such image processing.
Deepa Kasaragod - One of the best experts on this subject based on the ideXlab platform.
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machine learning based segmentation of the optic nerve head using multi contrast Jones Matrix optical coherence tomography with semi automatic training dataset generation
Biomedical Optics Express, 2018Co-Authors: Deepa Kasaragod, Shuichi Makita, Youngjoo Hong, Yoshiaki YasunoAbstract: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 trained classifier. The feature engineering process generates synthetic features from the primary optical contrasts obtained by JM-OCT. The tissue classification is performed in the feature space of the engineered features. We applied this framework to the in vivo analysis of optic nerve heads of posterior eyes. This classified each JM-OCT pixel into prelamina, lamina cribrosa (lamina beam), and retrolamina tissues. The lamina beam segmentation results were further utilized for birefringence and attenuation coefficient analysis of lamina beam.
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generation and optimization of superpixels as image processing kernels for Jones Matrix optical coherence tomography
Biomedical Optics Express, 2017Co-Authors: Arata Miyazawa, Shuichi Makita, Youngjoo Hong, Deepa Kasaragod, Yoshiaki YasunoAbstract: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 and statistical accuracy. We introduce a superpixel method to JM-OCT for generating the flexible kernels of local statistics. A superpixel is a cluster of image pixels that is formed by the pixels’ spatial and signal value proximities. An algorithm for superpixel generation specialized for JM-OCT and its optimization methods are presented in this paper. The spatial proximity is in two-dimensional cross-sectional space and the signal values are the four optical features. Hence, the superpixel method is a six-dimensional clustering technique for JM-OCT pixels. The performance of the JM-OCT superpixels and its optimization methods are evaluated in detail using JM-OCT datasets of posterior eyes. The superpixels were found to well preserve tissue structures, such as layer structures, sclera, vessels, and retinal pigment epithelium. And hence, they are more suitable for local statistics kernels than conventional uniform rectangular kernels.
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three dimensional multi contrast imaging of in vivo human skin by Jones Matrix optical coherence tomography
Biomedical Optics Express, 2017Co-Authors: Shuichi Makita, Youngjoo Hong, Deepa Kasaragod, Yoshiaki YasunoAbstract: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. To evaluate the performance of this JM-OCT, we measured in vivo human skin at several locations. Using the four kinds of OCT contrasts, the morphological characteristics and optical properties of different skin types were visualized.
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birefringence and vascular imaging of in vivo human skin by Jones Matrix optical coherence tomography
Proceedings of SPIE, 2017Co-Authors: Shuichi Makita, Youngjoo Hong, Deepa Kasaragod, Yoshiaki YasunoAbstract: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 of the epithelium were observed with depth-resolved local birefringence and polarization uniformity images. These results suggest high diagnostic and investigative potential of JM-OCT for dermatology.
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optimization method of superpixel analysis for multi contrast Jones Matrix tomography conference presentation
Proceedings of SPIE, 2017Co-Authors: Arata Miyazawa, Shuichi Makita, Youngjoo Hong, Masahiro Miura, Deepa Kasaragod, Yoshiaki YasunoAbstract:Local statistics are widely utilized for quantification and image processing of OCT. For example, local mean is used to reduce speckle, local variation of polarization state (degree-of-polarization-uniformity (DOPU)) is used to visualize melanin. Conventionally, these statistics are calculated in a rectangle kernel whose size is uniform over the image. However, the fixed size and shape of the kernel result in a tradeoff between image sharpness and statistical accuracy. Superpixel is a cluster of pixels which is generated by grouping image pixels based on the spatial proximity and similarity of signal values. Superpixels have variant size and flexible shapes which preserve the tissue structure. Here we demonstrate a new superpixel method which is tailored for multifunctional Jones Matrix OCT (JM-OCT). This new method forms the superpixels by clustering image pixels in a 6-dimensional (6-D) feature space (spatial two dimensions and four dimensions of optical features). All image pixels were clustered based on their spatial proximity and optical feature similarity. The optical features are scattering, OCT-A, birefringence and DOPU. The method is applied to retinal OCT. Generated superpixels preserve the tissue structures such as retinal layers, sclera, vessels, and retinal pigment epithelium. Hence, superpixel can be utilized as a local statistics kernel which would be more suitable than a uniform rectangle kernel. Superpixelized image also can be used for further image processing and analysis. Since it reduces the number of pixels to be analyzed, it reduce the computational cost of such image processing.
Rajendra Bhandari - One of the best experts on this subject based on the ideXlab platform.
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transpose symmetry of the Jones Matrix and topological phases erratum
Optics Letters, 2008Co-Authors: Rajendra BhandariAbstract:In an earlier Letter [Opt. Lett.33, 854 (2008)] a statement regarding Matrix S was incorrect; this error is corrected here.
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transpose symmetry of the Jones Matrix and topological phases
Optics Letters, 2008Co-Authors: Rajendra BhandariAbstract:The transmission Jones Matrix of an arbitrary stack of reciprocal plane-parallel plates that has been turned through 180° about an axis in the plane of the stack is, in an appropriate basis, the transpose of the transmission Matrix of the unturned slab with a change in the sign of the off-diagonal elements. We prove this convention-free result for the case where reflection at the interfaces can be ignored and use it to devise an experimental scheme to separate isotropic and topological phase changes in a reciprocal optical medium.
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transpose symmetry of the Jones Matrix and topological phases
arXiv: Optics, 2008Co-Authors: Rajendra BhandariAbstract:The transmission Jones Matrix of an arbitrary stack of reciprocal plane parallel plates which has been turned through 180 degrees about an axis in the plane of the stack is, in an appropriate basis, the transpose of the transmission Matrix of the unturned slab with a change in the sign of the off-diagonal elements. We prove this convention-free result for the case where reflection at the interfaces can be ignored and use it to devise an experimental scheme to separate isotropic and topological phase changes in a reciprocal optical medium.
