WI-VI TECHNOLOGY

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A Presentation on

ByShashidhar.S.K

CONTENTS

Introduction

Wireless vision

Eliminating the flash effect

Identifying and tracking humans

Applications, Merits and Demerits

Conclusion

Reference

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INTRODUCTION

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Wi-Vi stands for wireless vision.

Wi-Vi is used to detect the humans behind the wall.

Wi-Vi is a three antenna device with two transmitters and one receiver.Signals transmitted are similar but inverse of 1st antenna.

Earlier operation to detect humans behind wall used antenna array and UWB frequencies made them bulky.

Key Idea

WI-VI DEVICE

Figure1 :Key idea for working of WI-VI

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The key idea behind this technology is the reflection of the signals which is similar to that of RADAR and SONAR imaging.

WIRELESS VISION

Captures moving objects behind wall Makes use of WI-FI signals and hardware Uses WI-FI signals ISM bands at 2.4Ghz but limits

to 20 MHz After traversing the wall twice the signal power is reduced by 3-5 orders of their magnitudeThe reflections from the wall is much more stronger

than that of humans this reflection overwhelm the signals reflected from the human and prevents it from registering minute variations called as FLASH EFFECT

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Figure 2: Wi-Vi Setup

WHERE TO INSTALL THE DEVICE ?

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ELIMINATING THE FLASH EFFECT

There are three steps involved Initial nulling Power boosting Iterative nullingThese combined process is known as MIMO nulling

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8MIMO CASES

θ

Antenna Array

Direction of motion

At any point in time, we have a single measurement

Direction of reflection

WI-VI DEVICE

IDENTFYING AND TRACKING OF HUMANS

Figure 5:ISAR 9

θ

Antenna Array

Tracking Motion

Direction of motion

Direction of motion

θ

WI-VI DEVICEFigure 6:ISAR 10

Identifying and tracking humans

One moving person is indicated by a single curved line

Figure 7: output for single human 11

Tracking Multiple Humans

Number of distinct curves at the same time corresponds to the number of humans

Figure 8 output for two Humans 12

Figure 9 output for three Humans

Figure 10: Detection Accuracy of Wi-Vi for Different Types of Obstructions

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ApplicationsFigure 11:Law enforcement

Figure 12:Emergency situations

Figure 13:Personal security Figure 14:Gesture interface from behind a wall

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Merits High efficiency. Low power, low cost and low bandwidth. It overcomes the need for UWB by using MIMO nulling to remove the flash effect. No connectors. Ease of installation.

Demits Low resolution. Short range of communication.

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CONCLUSION

Could prove to be very powerful and effective device for defence purposes.

Possibly the next generation RADAR.

Further improvement will allow WI-VI to become more expressive hence hoping new directions of virtual reality.

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REFERENCE

[1] “See Through Walls with Wi-Fi!” by FadelAdibandDinaKatabi Massachusetts Institute of Technology {fadel,dk}@mit.edu.August 2013

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[2] http://people.csail.mit.edu/fadel/wivi/

[3] http://geekshots.in/2013/12/16/wi-vi-wifi-vision-vision- behind-the-walls/

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