Dr. Takashi Obi Profile

Dr. Takashi Obi

Associate Professor at Institute of Science Tokyo

SPIE Involvement:

Author

Publications (31)

SPIE Journal Paper | 31 May 2023 Open Access

Generative adversarial network based digital stain conversion for generating RGB EVG stained image from hyperspectral H&E stained image

Tanwi Biswas, Hiroyuki Suzuki, Masahiro Ishikawa, Naoki Kobayashi, Takashi Obi

JBO, Vol. 28, Issue 05, 056501, (May 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.5.056501

KEYWORDS: Hyperspectral imaging, RGB color model, Elasticity, Education and training, Tissues, Image quality, Collagen, Digital imaging, Data modeling, Data conversion

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SignificanceQuantification of elastic fiber in the tissue specimen is an important aspect of diagnosing different diseases. Though hematoxylin and eosin (H&E) staining is a routinely used and less expensive tissue staining technique, elastic and collagen fibers cannot be differentiated using it. So, in conventional pathology, special staining technique, such as Verhoeff’s van Gieson (EVG), is applied physically for this purpose. However, the procedure of EVG staining is very expensive and time-consuming.AimThe goal of our study is to propose a deep-learning-based computerized method for the generation of RGB EVG stained tissue from hyperspectral H&E stained one to save the time and cost of conventional EVG staining procedure.ApproachH&E stained hyperspectral image and EVG stained RGB whole slide image of human pancreatic tissue have been leveraged for this experiment. CycleGAN-based deep learning model has been proposed for digital stain conversion while images from source and target domains are of different modalities (hyperspectral and RGB) with different channel dimensions. A set of three basis functions have been introduced for calculating one of the losses of the proposed method, which retains the relevant features of EVG stained image within the reduced channel dimension of the H&E stained one.ResultsThe experimental results showed that a set of three basis functions including linear discriminant function and transmittance spectrum of eosin and hematoxylin better retained the essential properties of the elastic fiber to be discriminated from collagen fiber within the reduced dimension of the hyperspectral H&E stained image. Also, only a smaller number of paired training data with our proposed training method contributed significantly to the generation of more realistic EVG stained image with more precise identification of elastic fiber.ConclusionsRGB EVG stained image is generated from hyperspectral H&E stained image for which our model has performed two types of image conversion simultaneously: hyperspectral to RGB and H&E to EVG. The experimental results show that the intentionally designed set of three basis functions contains more relevant information and prove the effectiveness of our proposed method in generating realistic RGB EVG stained image from hyperspectral H&E stained one.

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Proceedings Article | 7 April 2023 Presentation + Paper

Generation of RGB EVG stained image from hyperspectral H&E stained image using generative adversarial network (GAN)

Tanwi Biswas, Hiroyuki Suzuki, Masahiro Ishikawa, Naoki Kobayashi, Takashi Obi

Proceedings Volume 12471, 124710D (2023) https://doi.org/10.1117/12.2653491

KEYWORDS: Hyperspectral imaging, Tissues, Histopathology, Deep learning, Image processing

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SPIE Journal Paper | 31 October 2022 Open Access

Hyperspectral imaging for tumor segmentation on pigmented skin lesions

Eleni Aloupogianni, Takaya Ichimura, Mei Hamada, Masahiro Ishikawa, Takuo Murakami, Atsushi Sasaki, Koichiro Nakamura, Naoki Kobayashi, Takashi Obi

JBO, Vol. 27, Issue 10, 106007, (October 2022) https://doi.org/10.1117/12.10.1117/1.JBO.27.10.106007

KEYWORDS: Tumors, Tissues, Skin, Image segmentation, Pathology, Data modeling, Tumor growth modeling, 3D modeling, Hyperspectral imaging, Convolution

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SPIE Journal Paper | 8 June 2022 Open Access

Hyperspectral and multispectral image processing for gross-level tumor detection in skin lesions: a systematic review

Eleni Aloupogianni, Masahiro Ishikawa, Naoki Kobayashi, Takashi Obi

JBO, Vol. 27, Issue 06, 060901, (June 2022) https://doi.org/10.1117/12.10.1117/1.JBO.27.6.060901

KEYWORDS: Multispectral imaging, Skin, Tissues, Tumors, Image processing, Cameras, Melanoma, Hyperspectral imaging, Reflectivity, Image segmentation

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Proceedings Article | 27 October 2021 Paper

Finger region extraction using color of skin for hand-waving finger vein authentication

Hiroyuki Suzuki, Narissa Ditthapakdijanya, Takashi Komuro, Keiichiro Kagawa, Kazuya Nakano, Takashi Obi

Proceedings Volume 11925, 119250X (2021) https://doi.org/10.1117/12.2615690

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Proceedings Article | 15 February 2021 Poster + Presentation + Paper

Effect of formalin fixing on chromophore saliency maps derived from multi-spectral macropathology skin images

Eleni Aloupogianni, Hiroyuki Suzuki, Takaya Ichimura, Atsushi Sasaki, Hiroto Yanagisawa, Tetsuya Tsuchida, Masahiro Ishikawa, Naoki Kobayashi, Takashi Obi

Proceedings Volume 11603, 116030W (2021) https://doi.org/10.1117/12.2581926

KEYWORDS: Skin, Chromophores, Tissues, Multispectral imaging, Hemodynamics, Absorption, Statistical analysis, RGB color model, Pathology, In vivo imaging

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Proceedings Article | 19 March 2014 Paper

Image reconstruction for the new simultaneous whole-body openPET/CT geometry

Yannan Yin, Hideaki Tashima, Takashi Obi, Taiga Yamaya

Proceedings Volume 9033, 90334M (2014) https://doi.org/10.1117/12.2043219

KEYWORDS: X-ray computed tomography, Sensors, Positron emission tomography, Image quality, Reconstruction algorithms, Image quality standards, Image restoration, Image processing, Scanners, X-ray sources

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Proceedings Article | 3 November 2011 Paper

Quantitative analysis on key estimation by known-plaintext attacks to DRPE

Kazuya Nakano, Hiroyuki Suzuki, Masahiro Yamaguchi, Takashi Obi, Nagaaki Ohyama

Proceedings Volume 8011, 80117V (2011) https://doi.org/10.1117/12.903356

KEYWORDS: Image encryption, Fourier transforms, Phase retrieval, Optical image encryption, Quantitative analysis, Image analysis, Computer programming, Resistance, Computer security, Modulation

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Proceedings Article | 18 March 2008 Paper

A feasibility study of the 3D fluorescent image reconstruction for the simultaneous PET and fluorescent CT imaging system using depth of interaction PET detector

Hideaki Tashima, Takashi Obi, Taiga Yamaya, Hideo Murayama, Keiji Kitamura, Ichiro Oda, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 6913, 691341 (2008) https://doi.org/10.1117/12.771370

KEYWORDS: Sensors, Positron emission tomography, Near infrared, Computed tomography, Image resolution, 3D image reconstruction, Imaging systems, 3D image processing, Tissues, Matrices

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Proceedings Article | 7 September 2006 Paper

Micro-CT of small insects by projection x-ray microscopy

Akira Tanisako, Susumu Tsuruta, Ayumi Hori, Aya Okumura, Chikara Miyata, Chiaki Kuzuryu, Takashi Obi, Hideyuki Yoshimura

Proceedings Volume 6318, 63180B (2006) https://doi.org/10.1117/12.679780

KEYWORDS: X-rays, Metals, X-ray microscopy, Microscopes, Absorption, Cobalt, Iron, Scanning electron microscopy, Electron beams, 3D acquisition

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Proceedings Article | 2 March 2006 Paper

Correction of inter-crystal scatter effect in iterative image reconstruction of the jPET-D4

Chih Fung Lam, Naoki Hagiwara, Takashi Obi, Masahiro Yamaguchi, Taiga Yamaya, Hideo Murayama

Proceedings Volume 6142, 614252 (2006) https://doi.org/10.1117/12.652503

KEYWORDS: Crystals, Sensors, Error control coding, Monte Carlo methods, Image restoration, Positron emission tomography, Scanners, Scintillation, Gamma radiation, Photonic crystals

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SPIE Journal Paper | 1 October 2004

Color conversion method for multi-primary display for spectral color reproduction

Yuri Murakami, Jun-ichiro Ishii, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

JEI, Vol. 13, Issue 04, (October 2004) https://doi.org/10.1117/12.10.1117/1.1785800

KEYWORDS: Color reproduction, Visualization, Light emitting diodes, Switching, LED displays, Control systems, Telecommunications, Optimization (mathematics), Integrating spheres, Standards development

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Proceedings Article | 13 July 2004 Paper

Enhancement of spectral change from change of cell nucleus size distribution in epithelium using multiclass linear discriminant

Kazuhiro Gono, Makoto Igarashi, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 5326, (2004) https://doi.org/10.1117/12.528902

KEYWORDS: Tissues, Scattering, Monte Carlo methods, Reflectivity, Particles, Mie scattering, Tissue optics, Light scattering, Endoscopy, Cameras

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SPIE Journal Paper | 1 May 2004 Open Access

Appearance of enhanced tissue features in narrow-band endoscopic imaging

Kazuhiro Gono, Takashi Obi, Masahiro Yamaguchi, Nagaaki Oyama, Hirohisa Machida, Yasushi Sano, Shigeaki Yoshida, Yasuo Hamamoto, Takao Endo

JBO, Vol. 9, Issue 03, (May 2004) https://doi.org/10.1117/12.10.1117/1.1695563

KEYWORDS: Visualization, Endoscopy, Capillaries, Image filtering, Optical filters, Endoscopes, Cancer, Blood vessels, Tongue, Video

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Proceedings Article | 18 January 2004 Paper

Multispectral image compression for high-quality color reproduction using JPEG2000

Ryota Mase, Yohei Kawasaki, Yuri Murakami, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 5308, (2004) https://doi.org/10.1117/12.528139

KEYWORDS: Image compression, Multispectral imaging, Image restoration, JPEG2000, Color reproduction, Reflectivity, Quantization, Color difference, Astatine, Imaging systems

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Proceedings Article | 23 October 2003 Paper

Fingerprint verification for smart-card holders based on an optical image encryption scheme

Hiroyuki Suzuki, Taiga Yamaya, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 5202, (2003) https://doi.org/10.1117/12.506645

KEYWORDS: Optical image encryption, Image encryption, Holograms, Computing systems, Sensors, Computer simulations, Image processing, Binary data, Biometrics, Fourier transforms

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Proceedings Article | 29 July 2003 Paper

Simulation of spectral reflectance of multiple scattering medium using the Mie theory combined with Monte Carlo method

Makoto Igarashi, Kazuhiro Gono, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 4955, (2003) https://doi.org/10.1117/12.478215

KEYWORDS: Tissues, Particles, Monte Carlo methods, Mie scattering, Reflectivity, Scattering, Tissue optics, Refractive index, Optical fibers, Light scattering

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Proceedings Article | 2 July 2003 Paper

Color enhancement in multispectral image of human skin

Masanori Mitsui, Yuri Murakami, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 4959, (2003) https://doi.org/10.1117/12.477944

KEYWORDS: Image enhancement, Multispectral imaging, Skin, Visualization, Medical imaging, Color reproduction, Cameras, Image processing, RGB color model, Reflectivity

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Proceedings Article | 7 January 2002 Paper

X-ray computed tomography using projection x-ray microscope

Hideyuki Yoshimura, Chikara Miyata, Chiaki Kuzuryu, Ayumi Hori, Takashi Obi, Nagaaki Ohyama

Proceedings Volume 4503, (2002) https://doi.org/10.1117/12.452841

KEYWORDS: X-rays, Microscopes, Metals, CCD cameras, X-ray sources, 3D image processing, 3D image reconstruction, Electron beams, Gold, X-ray computed tomography

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Proceedings Article | 21 December 2000 Paper

High-fidelity image reproduction using angular distribution of reflected spectral intensity

Masaru Tsuchida, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 4300, (2000) https://doi.org/10.1117/12.410783

KEYWORDS: Reflection, Light sources, Specular reflections, Cameras, Multispectral imaging, Telecommunications, Imaging systems, Color reproduction, Color imaging, Visualization

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Proceedings Article | 25 April 2000 Paper

Expanded color gamut reproduced by six-primary projection display

Takeyuki Ajito, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 3954, (2000) https://doi.org/10.1117/12.383364

KEYWORDS: Projection systems, RGB color model, Solids, LCDs, Optical filters, CRTs, Linear filtering, Color reproduction, Light sources, Distortion

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SPIE Journal Paper | 1 November 1999

Multiprimary color display for liquid crystal display projectors using diffraction grating

Takeyuki Ajito, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

OE, Vol. 38, Issue 11, (November 1999) https://doi.org/10.1117/12.10.1117/1.602276

KEYWORDS: LCDs, Diffraction gratings, Diffraction, Projection systems, CRTs, Microlens array, RGB color model, Neodymium, Light sources, Chromatic aberrations

Proceedings Article | 28 May 1999 Paper

Fast estimation of scatter components with good accuracy by using OS-EM techniques for scatter subtraction

Zheng Liu, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349482

KEYWORDS: Expectation maximization algorithms, Optical spheres, Reconstruction algorithms, Image processing, Monte Carlo methods, Image analysis, Signal attenuation, Single photon emission computed tomography, Signal to noise ratio, Image quality

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Proceedings Article | 21 May 1999 Paper

Pattern-histogram-based temporal change detection using personal chest radiographs

Yucel Ugurlu, Takashi Obi, Akira Hasegawa, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 3661, (1999) https://doi.org/10.1117/12.348525

KEYWORDS: Image registration, Chest imaging, Visualization, Vector spaces, Lung, Opacity, Radiography, 3D image processing, Diagnostics, Image analysis

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Proceedings Article | 26 June 1998 Paper

Natural color reproduction of human skin for telemedicine

Yuri Ohya, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama, Yasuhiro Komiya

Proceedings Volume 3335, (1998) https://doi.org/10.1117/12.312499

KEYWORDS: Skin, Cameras, Reflectivity, Color reproduction, Telemedicine, Imaging systems, Visualization, Telecommunications, Multispectral imaging, Statistical analysis

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Proceedings Article | 24 June 1998 Paper

Hierarchical clustering method for the segmentation of medical images

Keiko Ohkura, Hidezaku Nishizawa, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 3338, (1998) https://doi.org/10.1117/12.310859

KEYWORDS: Image segmentation, Medical imaging, Particles, Vector spaces, Image analysis, Thermodynamics, Image processing, Intestine, Statistical analysis, Digital imaging

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Proceedings Article | 1 February 1998 Paper

Block-cipher scheme based on back iteration of the 2D cellular automata

Maria Madjarova, Mitsugu Kakuta, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 3228, (1998) https://doi.org/10.1117/12.300908

KEYWORDS: Computer security, Binary data

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Proceedings Article | 7 May 1997 Paper

Natural color reproduction in the television system for telemedicime

Masahiro Yamaguchi, Ryo Iwama, Yuri Ohya, Takashi Obi, Nagaaki Ohyama, Yasuhiro Komiya, Toshiaki Wada

Proceedings Volume 3031, (1997) https://doi.org/10.1117/12.273926

KEYWORDS: Cameras, Color reproduction, Imaging systems, Multispectral imaging, Televisions, Telecommunications, Telemedicine, CRTs, Human vision and color perception, Reflectivity

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Proceedings Article | 25 April 1997 Paper

Color measurement of the mucous membrane using sequential endoscopic images

Shin-ichiroh Kitoh, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 3034, (1997) https://doi.org/10.1117/12.274084

KEYWORDS: Endoscopes, Charge-coupled devices, Endoscopy, Reflectivity, Reflection, Optical filters, Imaging systems, Natural surfaces, Statistical analysis, Image analysis

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Proceedings Article | 25 April 1997 Paper

Correction method for shift-variant characteristics of the SPECT measurement system

Masahiro Mimura, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 3034, (1997) https://doi.org/10.1117/12.274094

KEYWORDS: Single photon emission computed tomography, Photons, Sensors, Signal attenuation, Collimators, Data acquisition, Imaging systems, Numerical simulations, Data conversion, Numerical integration

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Proceedings Article | 11 November 1996 Paper

Hierarchical clustering method for the analysis of large amounts of data

Hidezaku Nishizawa, Takashi Obi, Masahiro Yamaguchi, Nagaaki Ohyama

Proceedings Volume 2824, (1996) https://doi.org/10.1117/12.258130

KEYWORDS: Medicine, Electrocardiography, Diagnostics, Statistical analysis, Multidimensional signal processing, Databases, Imaging systems, Digital imaging, Medical imaging, Computer simulations

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Showing 5 of 31 publications

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