Faculty Profiles - YAMAZATO Takaya

Papers - YAMAZATO Takaya

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3-215 Lectures in Nagoya University OCW that providing play and learning experiences Reviewed Open Access

Yamazato Takaya

Proceedings of Annual Conference of Japanese Society for Engineering Education Vol. 2013 ( 0 ) page： 268 - 269 2013

Accuracy improvement by phase only correlation for distance estimation scheme for visible light communications using an LED array and a high-speed camera Reviewed Open Access

Ohmura A., Yamazato T., Arai S., Yendo T., Fujii T., Okada H.

20th ITS World Congress Tokyo 2013 2013

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：20th ITS World Congress Tokyo 2013

In this paper, we focus on a distance estimation scheme using camera. Our distance estimation scheme is based on triangulation. The accuracy of camera based scheme is governed by resolution of a camera, or equivalently the size of pixel. Therefore we introduce phase only correlation (POC) to estimate with subpixel accuracy. As a result of experiment, we will show that our scheme achieves less than 0.3m estimation error at the distance of 60m. By using POC, the resolution of estimation reaches nearly 0.02 pixel, much less than one pixel.

Open Access

Scopus

Alamouti-Type Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

Yuta Amano, Koji Kamakura, Takaya Yamazato

2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM) page： 2430 - 2435 2013

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IEEE

This paper proposes Alamouti-type space time (ST) coding to visible light communication (VLC) using light emitting diodes (LEDs) and image sensor-based direct detection with a high-speed camera. Although multiple LEDs of an array are used as transmitters to communicate to individual pixel elements of an image sensor which act as multiple receive elements, the received signal is essentially the image of the transmitting element, whose size in pixel reduces with distance. When the receiver captures the LED array at a distance where images of two neighboring LEDs in the array are not separated at the image plane, such distortion depreciates the symbol decision quality. Our proposed scheme aims at expanding the communication range limited by the pixel resolution of image sensor. Our implemented prototype demonstrates that ST coding is feasible to achieve 48-meter error-free transmission range while the repetition transmission achieves 26-m error-free range.

DOI： 10.1109/GLOCOM.2013.6831438

Web of Science

Scopus

researchmap

Channel Information Estimation for Error Correcting Code in Road-to-Vehicle Visible Light Communication Systems Reviewed

Okada Hiraku, Misawa Shinnosuke, Yamazato Takaya, Fujii Toshiaki, Yendo Tomohiro

2013 IEEE 5TH INTERNATIONAL SYMPOSIUM ON WIRELESS VEHICULAR COMMUNICATIONS (WIVEC) 2013

Alamouti-Type Coding for Visible Light Communication Based on Direct Detection Using Image Sensor Reviewed

Amano Yuta, Kamakura Koji, Yamazato Takaya

2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM) page： 2430 - 2435 2013

Intensity estimation method of LED array for visible light communication Reviewed

Takanori Ito, Tomohiro Yendo, Shintaro Arai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii

Proceedings of SPIE - The International Society for Optical Engineering Vol. 8663 2013

Language：English Publishing type：Research paper (international conference proceedings)

This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small. © 2013 SPIE-IS&amp
T.

DOI： 10.1117/12.2005738

Scopus

researchmap

Interpixel Interference Cancellation Method for Road-to-Vehicle Visible Light Communication Reviewed

Kasashima Tatsuya, Yamazato Takaya, Okada Hiraku, Fujii Toshiaki, Yendo Tomohiro, Arai Shintaro

2013 IEEE 5TH INTERNATIONAL SYMPOSIUM ON WIRELESS VEHICULAR COMMUNICATIONS (WIVEC) 2013

Utilization of spatio-temporal image for LED array acquisition in Road to Vehicle Visible Light Communication Reviewed

Usui S.

20th ITS World Congress Tokyo 2013 2013

査読の虎の巻 Reviewed

山里敬也, 佐波孝彦, 塩田茂雄, 太田能

電子情報通信学会　通信ソサイエティマガジン Vol. 6 ( 3 ) page： 222 - 230 2013

A Study on the Simulator Development for Visible Light Communication Using LED and Camera Reviewed

T. Fukumoto, S. Arai, T. Yendo, T. Yamazato, H. Okada and T. Fujii

Proceedings of IEEE Workshop on Nonlinear Circuit Networks (NCN'12) ( pp. 124-127 ) page： - 2012.12

Language：English

This paper develops a simple simulation program for visible light communication (VLC) systems using LED (Transmitter) and a camera (Receiver). In the simulation, we generate an image of LED array transmitter which consists of LEDs arranged in a square matrix. In addition, effects of optical spatial channel, which is a unique channel in VLC, are constructed by using image processing techniques. We describe a system model of the VLC simulator and carry out the simulation with various parameters of the image processing.

Intensity estimation of LED array for parallel visible light communication Open Access

T. Ito, S. Arai, T. Yendo T. Yamazato, H. Okada and T. Fujii

Technical Report of IEICE ( CS2012-90 ) page： pp.113-118 2012.12

Visible light communication system using real-time software processing of high-speed camera image Open Access

M. Kasai, T. Yendo T. Yamazato, H. Okada, T. Fujii and S. Arai

Technical Report of IEICE ( CS2012-83 ) page： pp.71-75 2012.12

Intensity estimate of LED array for parallel Visible Light Communication Reviewed

ITO Takanori, YENDO Tomohiro, ARAI Shintaro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki

IEICE technical report. Image engineering Vol. 112 ( 335 ) page： 113 - 118 2012.12

Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs. To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small.

CiNii Research

Intensity estimate of LED array for parallel Visible Light Communication Reviewed

ITO Takanori, YENDO Tomohiro, ARAI Shintaro, YAMAZATO Takaya, Okada Hiraku, Fuji Toshiaki

IEICE technical report. Communication systems Vol. 112 ( 334 ) page： 113 - 118 2012.12

Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs. To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small.

CiNii Research

Visible light communication system using real-time software processing of high-speed camera image Reviewed

KASAI Makoto, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro

IEICE technical report. Image engineering Vol. 112 ( 335 ) page： 71 - 75 2012.12

Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

We focus on a road-to-vehicle Visible Light Communication (VLC) system using LED traffic light as the transmitter and high-speed camera as the receiver. Data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually. At the receiver side, the pattern is captured in the high-speed camera image. It is necessary to find the position of transmitter in the image and to extract the intensity of each LED at high-frame rate in real-time. In this paper, we achieve tracking of the transmitter and intensity extraction in real-time by only software processing on PC.

CiNii Research

Visible light communication system using real-time software processing of high-speed camera image Reviewed

KASAI Makoto, YENDO Tomohiro, YAMAZATO Takaya, OKADA Hiraku, FUJII Toshiaki, ARAI Shintaro

IEICE technical report. Communication systems Vol. 112 ( 334 ) page： 71 - 75 2012.12

Publishing type：Research paper (scientific journal) Publisher：The Institute of Electronics, Information and Communication Engineers

CiNii Research

The key to peer-review an IEICE article Reviewed Open Access

T. Yamazato, T. Saba, S. Shiota, C. Ohta

IEICE Communication Society Magazine Vol. No.23 [冬号] page： pp.222-230 2012.12

Multiple Information Sources Recognition Method for Ubiquitous Visible Light Communication Using on-Vehicle High-Speed Camera Reviewed Open Access

Y. Shiraki, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

IEICE Transactions on Communications Vol. J95-B ( 11 ) page： 1517-1528 2012.12

A Study on Error-Correcting Method for Noncoherent Chaos Communications Reviewed

S. Arai, Y. Nishio, T. Yamazato

Japan-Korea Joint Workshop on Complex Communication Sciences page： - 2012.11

Multiple Information Sources Recognition Method for Ubiquitous Visible Light Communication Using on-Vehicle High-Speed Camera Reviewed Open Access

Y. Shiraki, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai

IEICE Transactions on Communications Vol. J95-B ( no.11 ) page： pp.1517-1528 2012.11

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Papers - YAMAZATO Takaya