EYE GESTURE RECOGNITION TECHNOLOGY IN HUMAN-COMPUTER INTERACTION

ATHIRA J

S7 IT

ROLL NO:9

INTRODUCTION

Direct communication between humans and computers.

Depends on bioelectric signals.

Eye tracking means the estimation of direction of the user’s gaze.

Helpful for the disabled.

METHODS

Scleral search coil method Infrared Occulography (IROG)

Electro-Occulography (EOG)

Video Occulography (VOG)

INTRODUCTION TO ELECTRO-OCCULOGRAPHY Based on the relationship between eye movements

and electrode potentials from skin surface.

Cornea-Retina Potential

Current flows from retina side to Cornea side forming an electric field.

EOG signals are generated when eyes move from centre to left,right,up or down.

EOG value varies from 0.4 to 10mV with a frequency ranging from 0 to 100Hz.

ELECTRO-OCCULO GRAPHY Electrodes used : Ag-AgCl , Silicon –Rubber

Electrodes

MP150 and BIOPAC systems are adapted to acquire the EOG signals.

Emery papers and Electrolytic gel are used to improve conductivity.

When eyes move from centre to right or left, the horizontal EOG signals are obtained.

When eyes move from centre to up or down, the vertical EOG signals are generated.

Factors affecting EOG -Eyeball Rotation -Eyelid Movement -Electrode Placement -Head Movements -Lighting Conditions

Shift Resting Potential

When the gaze vector is within the angular range of ±50 horizontally and ±30 vertically, the EOG signals are almost proportional to the eye gaze.

ARDENS RATIO Amplitude of EOG signals decrease in dark

environment - Dark trough

Amplitude of EOG signals increase in bright light – Light peak

Ratio between light peak and dark trough is called Ardens Ratio.

If it is less than 1.8 it indicates a malfunction of the structures from which the potential originates.

EYE GESTURES RECOGNITION

There are 3 eye motion modes.

-Basic Eye Moving Mode

-Blink Mode

-Fixation Mode

1. RECOGNITION OF BASIC EYE MOVING MODE Gestures of eyes moving to right,left,down

and up are the basic moving modes.

Centre to left → Negative pulse Centre to right → Positive pulse Move up → Negative pulse Move down → Positive pulse

Diagonal eye movements are resolved into horizontal and vertical components.

2. RECOGNITION OF BLINKING MODE 3 Blink Modes -Voluntary -Involuntary -Reflexive

During eye blink eyeballs shoot upwards.

Compared to vertical EOG,pulse width are narrower.

3.FIXATION MODE AND MIDAS TOUCH PROBLEM Fixation mode usually refers to selection

operation.

Everywhere you look something gets activated-Midas Problem

Reason: Gaze only provides information about the coordinates on the screen and not about users intentions with the gaze.

Solution: Dwell-Time Activation

ADVANTAGES OF EOG EOG is linearly proportional to eye

displacement.

EOG signals are very fast.

Easy to use (in children and patients confined in bed).

Registration of eye movements with closed eyelids are possible.

Inexpensive

DISADVANTAGES OF EOG Short movements are difficult to record.

Large eye movements do not produce bioelectric amplitudes that are proportional to eye position.

Variation in skin resistance , electrode slippage etc affects EOG.

EOG signal increases with luminance.

APPLICATIONS Can be used in laptops,mobiles and other

electronic gadgets.

Browsing for disabled.

Used in Wheel Chairs.

Used in gaming.

EOG IN WHEEL CHAIRS

EOG signals are sent to PC which they are processed to calculate the eye gaze.

There exists a visual feedback system for the user to interact with the system.

Navigation methods used are classified into Manual and Auto Navigation.

Auto Navigation method has two basic behaviours

i)Motion Towards Target ii)Obstacle Boundary Following

CONCLUSION Eye gesture recognition is very important in

the design of eye-computer interface.

EOG method presents a good face access, good accuracy and resolution, real time work and is cheap.

EOG goggles are also available in market.

This technology is a boon for the disabled.

REFERENCES Min Lin and Guoming Mo, “Eye Gestures Recognition

Technology in Human-Computer Interaction”, 2011 4th International Conference on Biomedical Engineering and Informatics.

Hari Singh and Dr.Jaswinder Singh, “Human Eye Tracking and Related Issues: A Review” , International Journal of Scientific and Research Publications, Volume 2,Issue 9, September 2012.

Al-Haddad,R Sudirman and C.Omar , “Guiding Wheelchair Motion based on EOG Signals using Tangent Bug Algorithm” , 2011 Third International Conference on Computational Intelligence, Modelling & Simulation.

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