Detect moving objects behind walls with Wi-Vi technology
1. Wi-Vi Technology
1
: Wi-Fi that see through walls
Presented by –
Aman Raj
Indian Institute of
Technology(ISM),
Dhanbaddata:image/jpeg;base64,/9j/4AAQSkZJRgABAQA
2. Contents
Introduction
What can Wi-Vi do ?
Application
Design Methodology
Results
Advantages
Limitations
Future Scope
Conclusion
Bibliography 2
https://lh3.ggpht.com/UNrV_pPYCkgN3QK4T6Zotm3pevg3RcBuHH4DQV7e-wKoAYmHKMDGsW
3. Introduction
Wi-Vi stands for Wireless Vision.
Demonstrated by “Dina Katabi”, a MIT’s professor of
Electrical Department.
Wi-Vi uses OFDM signals in ISM Band(at 2.4 GHz) and
typical WiFi hardware.
Wi-Vi captures moving Objects behind the walls.
4. What can Wi-Vi do?
Detect the Number of Moving Humans in a
Closed Room.
Determine the Relative Location of Moving
Humans.
Enable Communication through a wall, without
carrying a Wireless Device.
Can Identify simple Gestures Behind a wall.
5. Continued
Wi-Vi device transmits two waves that cancel each other when
they reflect from a static object but not the moving object.
Wall is Static Disappears
People tend to move Detectable
6. Applications
Gesture control behind the wall
Police avoids ambush
Firefighters check for humans
Personel Security
https://url?sa=i&rct=j&q=&esrc=s&s
7. Design Methodology
Wi-Vi device consists of 3 parts; Wi-Fi signal, Transmitter and
Receiver.
Wi-Fi
Transmitter ReceiverWi-Vi
https://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=
8. Description of Wi-Vi: Wi-Fi device, Transmitter and Receiver
Wi-Fi Device
Receiver
Transmitter
https://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8
9. Wi-Vi Setup
Wi-Vi uses angle of arrival of signals to detect movement and no. of humans behind the wall.
https://www.google.co.in/imgres?imgurl=http%3A%2F%2Fwww.patrol-log.com%2Fwp-content%2Fuploads%2F2013%
10. Results
oA prototype of Wi-Vi setup used by Dina Katabi gave
the following results:
Wi-Vi can detect objects and humans moving behind
opaque structural obstructions.
This applies to 8” Concrete Walls, 6” Hollow walls
and 1.75” solid wooden doors.
11. Continued:
Wi-Vi depends upon the amount of movement.
To achieve a narrow beam, the human needs to move by
about 50cm.
Detected/Actual 0 1 2 3
0 100% 0% 0% 0%
1 0% 100% 0% 0%
2 0% 0% 85% 15%
3 0% 0% 15% 90%
Table. Accuracy of Automatic Detection of Humans.
12. Detection Accuracy of Wi-Vi for Different
types of obstructions:
80
82
84
86
88
90
92
94
96
98
100
102
Free Space Tinted Glass 1.75" solid wall 6" hollow wall 8" Concrete
Series 1
13. Advantages:
1. Wi-Vi requires only few MHz of bandwidth similar as
Wi-Fi.
2. Its setup is Low-Cost and Low-Power.
3. Wi-Vi can perform through wall imaging without
access to any device on the other side of the wall.
4. Works as extra human senses.
5. Allows to detect object in Dark or smoke.
14. Limitations
1.Display has very low Resolution.
2.Cannot detect human behind very thick
walls(>8” thickness).
3.Human needs to move at least 50 cm to be
detectable.
15. Future Scope:
Wi-Vi could be built into a Smartphone or a
special Handheld Device.
Can be used in Search and Rescue mission
by Fire Fighter and Law Enforcement.
16. Conclusion
Wi-Vi is a Wireless Technology that uses Wi-Fi
signals to detect moving humans behind walls
and in a closed rooms. In contrast to previous
systems, which are targeted for military, Wi-Vi
enables small cheap, see- through wall devices
that operates in the ISM band, rendering them
feasible tp the general public, without carrying
any extra transmitting device.
17. Bibliography
http://people.csail.mit.edu/fadel/wivi/
USRP N210. http://www.ettus.com. Ettus Inc.
X-box Kinect. http://www.xbox.com/ Microsoft/wivi
RadarVision. http://www.timedomain.com. Time Domain
Corporation
How Signal is affected. www.ci.cumberland.md.us/
See Through Walls with Wi-Fi! Fadel Adib and Dina Katabi
Massachusetts Institute of Technology {fadel,dk}@mit.edu