Research

Recognizing the ID of Modulated LED Tube Lights by Using Camera Motion Blur

  • Li Chang, Daisuke Iwai, and Kosuke Sato : Recognizing the ID of Modulated LED Tube Lights by Using Camera Motion Blur, IEEJ Transactions on Electrical and Electronic Engineering, Vol. 7, No. S1, pp. S96-S104, 2012.

Recognizing the ID of Modulated LED Tube Lights by Using Camera Motion Blur   In this paper, we present an image‐based ID recognition method for ID‐modulated light‐emitting diode (LED) tube lights by using the motion blur captured by a moving camera. This method is applied to a novel camera‐based indoor positioning system, which can provide exact location for mobile users. In this system, high‐intensity LED tubes are used concurrently as the illumination devices and optical markers. The flashing of each LED lamp is modulated, and the entire tube expresses an ID message, which can be captured by a normal camera installed in a mobile terminal. The flashing occurs at a high frequency and without degrading the illumination function. However, when the exposure time of the camera is longer than the flicker period of the LED lamps, it is difficult to capture the ID pattern. We propose a method that uses motion blur to overcome this limitation. During the period of exposure, if the user manually shakes the camera in the proper direction, a streaked pattern is developed on the captured image frame, which can be used for retrieving an ID number. Moreover, we can also obtain position estimation of the terminal from motion‐blurred images. Experimental results show that with careful operation it is feasible to recognize the ID of LED tubes successfully. c 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.   

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Indoor Navigation System using ID Modulated LED Tube Lights

  • Li Chang and Kosuke Sato : Indoor Navigation System using ID Modulated LED Tube Lights, IEEJ Transactions on Electrical and Electronic Engineering, Vol. 7, No. 5, pp. 514-520, 2012.

Indoor Navigation System using ID Modulated LED Tube Lights   This paper presents the design, implementation, and evaluation of a novel camera-based information transmission system for indoor positioning and navigation. This system, which avoids the use of any expensive equipment, is of particular benefit for infrastructure consumption and is completely portable using a handheld terminal. A high-intensity light-emitting diode (LED) tube, which is expected to be the main illumination source for the next generation due to its lower power cost and longer lifetime, is utilized as an optical beacon in the system. LED tubes are encoded to transmit ID information, which is received by a single normal camera. The handheld computing terminal, a mobile phone for example, can query a database after performing ID recognition and, finally, the position and orientation of the terminal can be obtained. Experimental results confirm the accuracy of the system in terms of both position and orientation, and it is suitable for many indoor navigation applications. c 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
  

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3D Localization in Ad Hoc Sensor Network with Embedded Camera and LEDs

  • Arata Hirokawa and Kosuke Sato, 3D Localization in Ad Hoc Sensor Network with Embedded Camera and LEDs, Transactions of the Society of Instrument and Control Engineers, Volume E-S-1, No.1, pp. 91-96 (2006).

3D Localization in Ad Hoc Sensor Network with Embedded Camera and LEDs
  In sensor networks, the location measure is one of the most important information. The simplest way to know the location of sensor nodes is to put a GPS receiver to each node. But this way is not suitable to indoor sensor networks. There are many researches of the location information. In this paper, we propose a new model for localizing in sensor networks with image sensing. We assume that the proposed models may be suitable to indoor sensor networks. Each sensor node, which mounts a camera and infrared LEDs, detects its 3D location by taking a set of images from the embedded camera. The 3D location information will be informed to other nodes via wireless communication. From simulations and experiments of a prototype sensor network with tiny CMOS embedded camera, we con・〉med that it is able to detect 3D location information based on the proposed 3D localizing models in a real scene.
  

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3D Localization and Optical Communication in Ad Hoc Sensor Network with Embedded Camera and LEDs

  • Arata Hirokawa and Kosuke Sato, 3D Localization and Optical Communication in Ad Hoc Sensor Network with Embedded Camera and LEDs, Second International Workshop on Networked Sensing Systems (INSS2004), pp. *-* (2005)

3D Localization and Optical Communication in Ad Hoc Sensor Network with Embedded Camera and LEDs
  In sensor networks, the location measurement is one of the most important research issues. In this paper, we propose amodel of sensor network for localizing in sensor networks with image sensing and optical communication. We assumethat the proposed system is suitable to indoor sensor networks, especially in case of radio noisy environments. Eachsensor node whose location is unknown captures an image sequence dynamically. The sensor node recognizes the ID ofreference location LED by capturing the blinking LEDs. The node obtains a set of the location information of the LEDsin the image sequence, and derives the 3D location itself. From simulations and experiments with a prototype sensornetwork, we confirm that it can detect the correct 3D location information with the proposed 3D localization model in areal scene.
  

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3D Localization in Ad-hoc Sensor Network with Embedded Cameras

  • Arata Hirokawa and Kosuke Sato, 3D Localization in Ad-hoc Sensor Network with Embedded Cameras, First International Workshop on Networked Sensing Systems (INSS2004), pp. 36-39 (2004).

3D Localization in Ad-hoc Sensor Network with Embedded Cameras
  In sensor networks, the location measure is one of the most important information. The simplest way to know the location of sensor nodes is to put a GPS receiver to each node. But this way is not suitable to indoor sensor networks. There are many researches about detecting the location information. In this paper, we propose a model for localizing in sensor networks with image sensing. We assume that the proposed system may be suitable indoor sensor networks. With each sensor node, which a camera and an infrared ray LED embedded, the network controls infrared LEDs of nodes and detects 3D location information of one node whose location is unknown with image processing. In the proposed system, the network turns on LEDs of nodes sequentially, whose 3D location is known, and a node whose location is unknown takes a set of image by the embedded camera, and 3D location information will be derived from the coordinates of nodes whose location is known in each captured image. From simulations and experiments with a prototype sensor network, we confirm that it can detect 3D location information with the proposed 3D localization model in a real scene.
  

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