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Optical Vehicle to Vehicle Communication System
Submitted by, Jisa T George S7 e c e Roll no:20
Guided by, Er.Elizabath Thomas (asst.prof.dep.of e c e)
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CONTENTS
Introduction
Overview of optical V2V communication system
Transmitter
Receiver
Optical communication image sensor
Future scope
Conclusion
Reference
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INTRODUCTION
Optical wireless communication technology
LED transmitters mounted on leading vehicle(L V)
Camera receiver mounted on following vehicle(F V)
Transmitting vehicle internal data & large multi-media data
higher data rate , accurate & quick LED detection
Camera receiver provides non-interference communication capability
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OVERVIEW OF OPTICAL V2V COMMUNICATION SYSTEM
fig: Illustration of the optical V2V communication system
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Vehicle LED source - tail lights , break lights and head lights
L V collects its own internal data
Sends these data to FV by optical signal(LED)
Using image processing techniques
Receiver system monitors light intensity variations
LED regions and optical signals are detected
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Transmitter
Fig: Photographs and block diagram of LED transmitter system
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Transmitter consists controller & LED array unit
Controller - collects , packetizes & encodes the data
LED array unit - consists of LED drivers & 10 10 LEDs
- Optical power up to 4 w
- Cut off frequency 55 MHz
870 nm near infrared LEDs are used
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Receiver
Fig:Photograph and block diagram of camera receiver system
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Fig. packet structure and communication specifications.
Data are picked from the packets
Encoding method is Manchester coding
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Measurement results of packet arrival & bit error rate
Received packets are counted
PAR decreases when FV pitched by uneven road
Increase output rate of flag image, packet losses reduced
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Optical Communication Image Sensor (OCI)
Fig: Entire operation of OCI
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CMOS image sensor technology
OCI pixel array consists of CPx & IPx array
IP x array captures images
CP x array receives optical signal
OCI outputs gray image & 1 bit flag image
Flag image - taken in short exposure time
- binarised by a comparator
- low intensity objects are eliminated
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Using flag image LED regions are detected
Coordinates of LED regions are obtained via image processing
Optical signals are outputted & amplified
Process repeated continuously & high speed optical signals received
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Optical V2V communication system
Fig: block diagram of optical V2V communication system
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Leading vehicle has 2 LED array units
Controller including a PC
Controller collects vehicle internal data
LED array units sends these data
Front view image compressed to jpeg format
Front view camera output images at up to 20 fps
FV has a camera receiver & a PC
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Fig : measurement method of inter-vehicle distance
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Relative speed between vehicles can calculate
Inter vehicle distance, L=(f/a).(D/n)
D=distance between left & right LED array units
f=lens focal length
n=number of pixel
a=IP x size
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Fig. Calculation result of the inter-vehicle distance for 50 seconds
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Fig.. Detection results of LED array units by using the flag image. (a), (b) Daytime lighting conditions.(c) Nighttime lighting condition. (d), (e) Daytime lighting conditions under which reflection regionsof the direct sunlight on the LV body exist. (f) Nighttime lighting condition under which brakelights of the LV are on.
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Fig. Reception result of vehicle internal data and front-view image in the daytime
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Fig. Reception result of vehicle internal data and front-view image in the nighttime.
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Future scope
Safety and comfort applications
Lane detection
Pedestrian detection
Long distance driving experiments
Experiments under more arduous lighting & movement conditions
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CONCLUSION
LED transmitter is capable of sending data by 10 Mb/s optical signals.
Flag image effectively eliminates unnecessary objects
Achieve real-time LED detection
Used for practical automotive applications
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REFERENCES
Isamu Takai ,Tomohisa Harada Optical vehicle to vehicle communication system using LED transmitter and camera receiver vol.6,no.5 oct.2014
P. Daukantas ,”optical wireless communications: The new ‘hot spots’?”opt.photon.news,vol.25,no.3,pp.33-41,mar.2014
D.O ’Brien, ” Visible light communications : Challenges and potential ,” in Proc . IEEE photon. conf.,oct.2011,pp.365-366
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