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Marking in the Surroundings by Data-Carriers for the Visually ... Marking in the Surroundings by Data-Carriers for the Visually ... Document Transcript

  • Marking in the Surroundings by Data-Carriers for the Visually Impaired Hisayuki Tatsumi † Yasuyuki Murai ‡ Nobuyuki Nagai ‡ Masahiro Miyakawa ‡ † Dept. of Computer Science, NTUT, Japan (National Univ. Corp., Tsukuba Univ. of Technology) ‡ School of Pharmacy, Nihon Pharmaceutical Univ., Japan
  • Abstract Purpose: • Building an information secured environment • for a visually impaired person • in our campus. He could know what happened in the surroundings by himself without the help of the sighted. Method: • To keep the environmental information we use RFID tags. • To trace the changes in the environment we use networks.
  • Approach: 1. In the mental map landmarks play a significant role. 2. We can turn any object into a landmark by attaching an RFID tag. 3. The changes could be recognized by recognizing changes of landmarks. We outline two methods to trace the changes of locations of RFID tags. 1. Detecting the moves of active RFID tags directly by analyzing the signals emitted from them. 2. Tracing the moves of passive RFID-tags by autonomous cruising robots.
  • The changes are: kept and updated in the network, conveyed to a visually impaired person according to his inquiry.
  • 1. The Problem An example: Detection of a move of a desk by a visually impaired person by himself. Solution: 1. he inquires to a network: what have happened with the desk? 2. the network can give an answer, as it keeps the changes of the environment. Method: Attach an RFID tag to the desk. Detect the move of the desk and register it to the network. We report two methods for the detection of the moves of RFID tags by: 1st: directly analyzing the signals from them. 2nd: tracing the changes of RFID tags by the RFID sensing robots. Our assumptions: Landmarks play a significant role in the mental map. A change in the environment can be considered as the changes (move) of the landmarks. Turning an object into a landmark by attaching an RFID to it.
  • 2. Marking in the environment by RFID Two types of RFID tags 1. passive RFID: has no electric power supply (its electric power comes from the reader by electro-magnetic induction). Memory capacity is limited (few 100-bytes). The communication range is short (from few centimeters to few 10-centimeters). Allows communication in both directions (i.e., writing in the tag is allowed as well as reading). 2. active RFID: has battery in it. Its communication range is larger (several meters). It allows only the emission of signals. By analyzing a signal received from the active RFID tag we may know, in principle, the direction and the distance of the RFID (object) as it serves as a small-powered radio beacon.
  • Marking We want to detect an environmental change caused by the moves of objects by marking the object by RFID tags. It arises in a laboratory or in a hallway.
  • 3. Active RFID tags and the detection of moves We indicate active RFID devices used in our experiment. The tag emits its identification number consisting of 6 alphabets and 8 digits) in every 7 seconds. Sensing the start and the end of the move of the object is easy, as a vibration sensor is set in the tag to detect the move of the tag. If we know differences both in directions and in intensities of the signals before and after the move, we may calculate the new location from the old one.
  • We have done a preliminary experiment detecting the intensities of signals as a function of distance (and possibly of directions) from the receiver. As a result we have seen that it is hardly possible to distinguish two tags by its intensities set apart by 20 cm placed in the extremely short distance of 40 cm from the receiver. We need a more careful study on this theme. Allocation of tags Intensity of electric field
  • 4. Tracking the moves of marks by RFID sensing robots The RFID sensing robot detects the changes of environment through autonomous cruising and keeps the environmental knowledge always up to date. Here we need a navigation (algorithm) of the robot. We describe our navigation program (a prototype). In the following way environmental knowledge is maintained in the network.
  • The robot is built on the platform of ER-1 (Evolution Robotics Inc.) It is attached a high-performance passive RFID reader/writer with 25cm effective antenna range. The robot is autonomous. The software named RCC (Robot Control Center) installed in the laptop carried on ER-1 controls both the sensor system consisting of CCD camera and IR (Infrared Radiation) sensors and the driving system. The navigation program is sent to RCC via telnet channel. Environmental information obtained by the robot (the content of RFID tags and the location of the robot) is sent to a server and kept there for a possible inquiry.
  • Our navigation program has successfully avoided both collisions and obstacles and found almost all objects. Environment in our experiment The robot reading a passive RFID tag attached to an object.
  • 5. Conclusive discussions and further problems To build an information ensured environment we have proposed an acquisition scheme of environmental information which issubject to change. 1. The use of RFID tags in marking in the environment and the RFID sensing robots to trace the environmental changes. 2. A possible use of active RFID tags for the detection of moves of objects. Fingings: on the use of active RFID to know the location of the object (current status): detection of the moves are hard
  • directly buzzering RFID tags is a practical solution. LED & buzzer Further studies: on the construction and maintaining the database of the environmetnal changes by autonoumous robots: Making a map of the environment -- Use of the autonomous robot to automatically build a map of the environment (cf. vSLAM technique). the grid map of our room
  • Danke ! Marking in the Surroundings by Data-Carriers for the Visually Impaired Masahiro Miyakawa Tsukuba University of Technology Acknowledgement: This work is supported in part by the Ministry of Education, Science, Sport and Culture, Grant-in-Aid for Scientific Research (C). No.18500700.