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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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