Electro Oculography 140811094948 Phpapp01

8/9/2019 Electro Oculography 140811094948 Phpapp01

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ELECTRO-OCULOGRAPHY

PRESENTED BY : TOWFEEQUMAR

ENROLL : 2551


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INTRO$"CTION

An eye controlled #ased on electro%oculography is designed to develop a

system or assisted mo#ility&

Assistive ro#otics can improve the 'uality o lie or disa#le people&

No( a days) there are many help systems to control and guideautonomous mo#ile ro#ots&

The system consists o a standard electric (heel chair) an on#oard

computer) sensors and a graphical user interace&


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$E*INITION Electrooculography +EOG, is a techni-ue or measuring the corneo%retinal

standing potential that e.ists #et(een the ront and the #ac/ o the humaneye& The resulting signal is called the E0ECTROOC"0OGRAM&

Measurement o eye movements is done #y placing pairs o electrodes

either a#ove and #elo( the eye or to the let and right o the eye&

I the eye moves rom center position to(ard one o the t(o electrodes) this

electrode sees the positive side o the Retina and the opposite electrode sees

the negative side o the retina& potential dierence occurs #et(een the

electrodes&

The recorded potential is a measure o the eye1s position&


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E0ECTROOC"0OGRAP2IC POTENTIA0

Measurement o electric potential #et(een electrodes placed at points close

to eye used to investigate eye movements especially in psychology

research&

The EOG ranges rom 3&34 to 5&4 m6 in humans and is linearly

proportional to eye displacement&

The human eye is an electrical dipole (ith a negative pole at the *undus

and a positive pole at the Cornea&


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PRINCIP0E

The eye acts as a dipole in (hich the anterior pole is positive and the

posterior pole is negative&

1. Left gaze: The Cornea approaches the electrode near the outer Canthus o

the let eye) resulting in a negative%trending change in the recorded

potential dierence&

2. Right gaze: the Cornea approaches the electrode near the inner Canthus o

the let eye) resulting in a positive % trending change in the recorded potential dierence&


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AR$EN RATIO

The Electro%Oculogram ma/es an indirect measurement o the minimum

amplitude o the standing potential in the dar/ and then again at its pea/

ater the light rise& This is usually e.pressed ratio o 7light pea/ to dar/

trough7 and is reerred to as the Arden ratio&


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EYE MODEL BASED IN EOG (BIDIM-EOG)

*ig 8 9 :i $imensional :i Polar Model +:i$iMEOG,


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E;E MO$E0 :ASE$ IN EOG

AIM:

To design a system capa#le o o#taining the ga


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FUNCTION OF EACH BLOC:

FILTER eliminates the eects due to other #iopotentials) =ust as the #lin/s

over to the EOG signal& Its a #and pass ilter (ith a very small Cut o

re-uency +3&34 2< > 532


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*ig ? 9 Process Results To $etect The Eye Ga


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E;E MO6EMENTS !ACCA"E! : Rapid eye movement +a =ump, (hich is usually

con=ugate and under voluntary control&

!hen (e ma/e a saccadic movement to(ards a speciic o#=ect) then

the saccade can accurately land on the o#=ect or) commonly) either

overshoot or undershoot it) so giving rise to a su#se-uent small

corrective saccade to the o#=ect&

$uring a saccadic movement our vision is not completely eliminated

#ut it is considera#ly reduced +this is /no(n as !ACCA"IC

!UPPRE!!ION,&


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E;E MO6EMENTSPUR!UIT EYE MO#EMENT!

These are con=ugate eye movements (hich smoothly trac/ slo(ly moving

o#=ects in the visual ield&

They typically re-uire a moving o#=ect to elicit them and are not usually

under voluntary control&

Their purpose) partly) is to sta#ili


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E;E MO6EMENTS

#ERGENCE EYE MO#EMENT!

These are movements (here #oth eyes move in opposite hori


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E;E MO6EMENTS

#E!TIBULAR EYE MO#EMENT!:

The vesti#ulo%ocular rele. +6OR,) is a rele. eye movement that sta#ili


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G"I$ANCE O* A !2EE0C2AIR

*ig 5 9 !heel Chair Guidance System


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G"I$ANCE O* !2EE0 C2AIR

The aim o this control system is to guide an autonomous mo#ile ro#otusing the positioning o the eye into its or#it #y means o EOG signal&

*igure sho(s a diagram o the guidance system&

The EOG signal is recorded using Ag%AgCl electrodes and this data) #y

means o an ac-uisition system are sent to a PC) in (hich they are processed to calculate the eye ga


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CONTRO00ING RO:OTIC ARM

Fig 4 : Sy!"# A$%&i!"%!'$" A EOG E*"%!$+"

P*,%"#"!


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CONTRO00ING RO:OTIC ARM

I#*"#"!" +*'!i+ %+i! i $"%+$ig EEG , EOG T&" $"%+$ig .*+%/ $"$""! , i!"$0,%" ."!""&yi%,* "i%"3 '" 0+$ ig,* ,%'ii!i+3 , %+#'!"$3'" 0+$ ig,* $+%"ig

F+$ "y" #+"#"! ""!3 , $",*-!i#" ,!!"$ $"%+gi!i+,*g+$i! , i#*"#"!" T&" ,*g+$i! $"%+gi6",*'" 0+$ ,#*i!'" , i!& '$ig , $"'"!" ,%!i+

EOG .," %+!$+* #+"* ,'#" "y" ,%%," 0+$+.7"%! "*"%!i+ , +'.*" "y" .*i/ig ""! 0+$ g$i"$%*+'$" A "y" ,%%," $"$""! , +!"!i,* ,$i,!i+ +0,$+' 289 0+$ ",%& "g$"" +0 "y" #+"#"!


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APP0ICATIONS G&i'a()e *f a +hee,)hai

A *ta/,e +ie,e00 ee *3ee(t )*(t*,,e' H&a( C*(t*,,e

I(tefa)e f* the 'i0a/,e'

It has our parts9

Surace electrodes&T(o%channel ampliier&

0aptop&

ig#ee (ireless module&

U0e' f* e*,e 0&ffei(g f* the f*,,*+i(g 'i0*'e0:

Amyotrophic lateral sclerosis +A0S,&

:rainstem stro/e&

:rain or spinal cord in=ury&


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PLEASE REMEMBER ME IN YOUR PRAYERS IF YOU LI;E MYWOR;


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A$6ANTAGES

The EOG is easy to use&

The signals are measured (ith respect to the head&

Registration o eye movements (ith closed eyelids and during sleep are possi#le&

Eye movement data are analog and the sampling rate o a ollo(ing analog%

digital%converter +A$C, can #e chosen reely&

The EOG is the most ine.pensive eye movement recording system&


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$ISA$6ANTAGES

Superposition o signals rom mimic or che(ing muscles +EMG,

$ependency on changes in CRP

$C%recordings al(ays have the pro#lem o drit superimposed on thesignal o interest


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CONC0"SION

Eye movements re-uire minimal eort and allo( direct selection

techni-ues) this increases the response time and the rate o

inormation lo(&

There are a lot o applications can #e developed using EOG #ecause

this techni-ue allo(s to users an ree degree in the environment&

Many applications can #e developed using EOG #ecause this

techni-ue provides the users (ith a degree o independence in the

environment&


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A N ; ' "

E R I E S P 0 E

A S E D D D D

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Electro Oculography 140811094948 Phpapp01