Electro Occulography is one of the best ways of measuring eye gestures. It is widely used in human computer interaction.

1. EYE GESTURE RECOGNITION
TECHNOLOGY IN HUMAN-
COMPUTER INTERACTION
ATHIRA J
S7 IT
ROLL NO:9

2. 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.

3. METHODS
 Scleral search coil method
 Infrared Occulography (IROG)
 Electro-Occulography (EOG)
 Video Occulography (VOG)

4. 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.

6. 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.

7.  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.

8. 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.

10. EYE GESTURES RECOGNITION
 There are 3 eye motion modes.
-Basic Eye Moving Mode
-Blink Mode
-Fixation Mode

11. 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.

13. 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.

15. 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

16. 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

17. 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.

18. APPLICATIONS
 Can be used in laptops,mobiles and other
electronic gadgets.
 Browsing for disabled.
 Used in Wheel Chairs.
 Used in gaming.

19. 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.

20.  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

21. 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.

22. 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.