Prof. Kiyotaka Sasagawa Profile

Prof. Kiyotaka Sasagawa

Associate Professor at Nara Institute of Science and Technology

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Publications (10)

SPIE Journal Paper | 30 June 2022 Open Access

Enhancing infrared color reproducibility through multispectral image processing using RGB and three infrared channels

Motoshi Sobue, Hiroshi Otake, Hironari Takehara, Makito Haruta, Hiroyuki Tashiro, Kiyotaka Sasagawa, Jun Ohta

OE, Vol. 61, Issue 06, 063107, (June 2022) https://doi.org/10.1117/12.10.1117/1.OE.61.6.063107

KEYWORDS: Infrared imaging, Image processing, Image enhancement, Infrared radiation, Multispectral imaging, Cameras, Signal processing, RGB color model, Infrared cameras, Optical engineering

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SPIE Journal Paper | 14 February 2022 Open Access

Modular head-mounted cortical imaging device for chronic monitoring of intrinsic signals in mice

Mark Christian Guinto, Makito Haruta, Yuki Kurauchi, Taisuke Saigo, Kazuki Kurasawa, Sumika Ryu, Yasumi Ohta, Mamiko Kawahara, Hironari Takehara, Hiroyuki Tashiro, Kiyotaka Sasagawa, Hiroshi Katsuki, Jun Ohta

JBO, Vol. 27, Issue 02, 026501, (February 2022) https://doi.org/10.1117/12.10.1117/1.JBO.27.2.026501

KEYWORDS: Information operations, Imaging devices, Sensors, Light emitting diodes, Brain, Head, Image sensors, Imaging systems, CMOS sensors, Blood circulation

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Significance: Intrinsic optical signals (IOS) generated in the cortical tissue as a result of various interacting metabolic processes are used extensively to elucidate the underlying mechanisms that govern neurovascular coupling. However, current IOS measurements still often rely on bulky, tabletop imaging systems, and there remains a dearth of studies in freely moving subjects. Lightweight, miniature head-mounted imaging devices provide unique opportunities for investigating cortical dynamics in small animals under a variety of naturalistic behavioral settings. Aim: The aim of this work was to monitor IOS in the somatosensory cortex of wild-type mice by developing a lightweight, biocompatible imaging device that readily lends itself to animal experiments in freely moving conditions. Approach: Herein we describe a method for realizing long-term IOS imaging in mice using a 0.54-g, compact, CMOS-based, head-mounted imager. The two-part module, consisting of a tethered sensor plate and a base plate, allows facile assembly prior to imaging sessions and disassembly when the sensor is not in use. LEDs integrated into the device were chosen to illuminate the cortical mantle at two different wavelengths in the visible regime (λcenter: 535 and 625 nm) for monitoring volume- and oxygenation state-dependent changes in the IOS, respectively. To test whether the system can detect robust cortical responses, we recorded sensory-evoked IOS from mechanical stimulation of the hindlimbs (HL) of anesthetized mice in both acute and long-term implantation conditions. Results: Cortical IOS recordings in the primary somatosensory cortex hindlimb receptive field (S1HL) of anesthetized mice under green and red LED illumination revealed robust, multiphasic profiles that were time-locked to the mechanical stimulation of the contralateral plantar hindpaw. Similar intrinsic signal profiles observed in S1HL at 40 days postimplantation demonstrated the viability of the approach for long-term imaging. Immunohistochemical analysis showed that the brain tissue did not exhibit appreciable immune response due to the device implantation and operation. A proof-of-principle imaging session in a freely behaving mouse showed minimal locomotor impediment for the animal and also enabled estimation of blood flow speed. Conclusions: We demonstrate the utility of a miniature cortical imaging device for monitoring IOS and related hemodynamic processes in both anesthetized and freely moving mice, cueing potential for applications to some neuroscientific studies of sensation and naturalistic behavior.

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SPIE Journal Paper | 3 November 2021 Open Access

Ultrasmall compact CMOS imaging system for bioluminescence reporter-based live gene expression analysis

Joshua Philippe Olorocisimo, Jeric Briones, Kiyotaka Sasagawa, Makito Haruta, Hironari Takehara, Hiroyuki Tashiro, Norihiro Ishida-Kitagawa, Yasumasa Bessho, Jun Ohta

JBO, Vol. 26, Issue 11, 116002, (November 2021) https://doi.org/10.1117/12.10.1117/1.JBO.26.11.116002

KEYWORDS: Bioluminescence, Signal detection, Imaging systems, Interference (communication), Absorption filters, In vivo imaging, Phase only filters, Measurement devices, Copper indium disulfide, CMOS devices

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Proceedings Article | 21 February 2020 Paper

An implantable light source for in-vivo fluorescence image sensor

Kiyotaka Sasagawa, Erus Rustami, Hironari Takehara, Makito Haruta, Jun Ohta

Proceedings Volume 11235, 112350U (2020) https://doi.org/10.1117/12.2545482

KEYWORDS: Light emitting diodes, Light sources, Luminescence, Image sensors, Interference filters, Optical filters, Image filtering, In vivo imaging, Blue light emitting diodes, Imaging devices

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Proceedings Article | 21 February 2020 Presentation + Paper

Fabrication of thin composite emission filter for high-performance lens-free fluorescent imager

Erus Rustami, Kiyotaka Sasagawa, Thanet Pakpuwadon, Yasumi Ohta, Hironari Takehara, Makito Haruta, Jun Ohta

Proceedings Volume 11235, 112350F (2020) https://doi.org/10.1117/12.2546540

KEYWORDS: Optical filters, Image filtering, Composites, Plasma etching, Interference filters, Absorption filters, Image sensors, Laser liftoff, Etching, Sensors

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Proceedings Article | 18 March 2014 Paper

Dual-mode lensless imaging device for digital enzyme linked immunosorbent assay

Kiyotaka Sasagawa, Soo Heyon Kim, Kazuya Miyazawa, Hironari Takehara, Toshihiko Noda, Takashi Tokuda, Ryota Iino, Hiroyuki Noji, Jun Ohta

Proceedings Volume 8933, 89330N (2014) https://doi.org/10.1117/12.2039948

KEYWORDS: Imaging devices, Luminescence, Molecules, Glasses, Sensors, Spatial resolution, Collimation, Microscopes, Image sensors, CMOS sensors

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Proceedings Article | 7 March 2014 Paper

On-chip polarizer on image sensor using advanced CMOS technology

Kiyotaka Sasagawa, Norimitsu Wakama, Toshihiko Noda, Takashi Tokuda, Kiyomi Kakiuchi, Jun Ohta

Proceedings Volume 8974, 89740I (2014) https://doi.org/10.1117/12.2040012

KEYWORDS: Polarizers, Metals, CMOS technology, Image sensors, Standards development, Photodiodes, Visible radiation, Optical testing, Refractive index, Near infrared

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Proceedings Article | 5 March 2014 Paper

Implantable CMOS imaging device with absorption filters for green fluorescence imaging

Yoshinori Sunaga, Makito Haruta, Hironari Takehara, Yasumi Ohta, Mayumi Motoyama, Toshihiko Noda, Kiyotaka Sasagawa, Takashi Tokuda, Jun Ohta

Proceedings Volume 8928, 89280L (2014) https://doi.org/10.1117/12.2038948

KEYWORDS: Luminescence, Absorption filters, Imaging devices, Light emitting diodes, Green fluorescent protein, Transmittance, Interference filters, Image filtering, Brain, Image sensors

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Proceedings Article | 14 June 2004 Paper

Control of oscillation wavelength of a microsphere laser using a lambda/4-shifted grating

Kiyotaka Sasagawa, Zen-o Yonezawa, Jun Ohta, Masahiro Nunoshita

Proceedings Volume 5350, (2004) https://doi.org/10.1117/12.528559

KEYWORDS: Resonators, Glasses, Optical spheres, Laser resonators, Neodymium, Ions, Luminescence, Optical filters, Refractive index, Microscopy

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Proceedings Article | 25 June 2003 Paper

Nd3+- doped tellurite glass microsphere laser

Kiyotaka Sasagawa, Kazushi Kusawake, Jun Ohta, Masahiro Nunoshita

Proceedings Volume 4969, (2003) https://doi.org/10.1117/12.478985

KEYWORDS: Glasses, Prisms, Optical spheres, Laser glasses, Laser damage threshold, Objectives, Continuous wave operation, Silica, Refractive index, Neodymium

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Showing 5 of 10 publications

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