Initial work executed in the development of a robotic wheelchair system based on Electro-Oculography to help disabled people

1. Eye Interface Technology using
Electrooculography –
A Proposed Model
PRESENTED BY:
SNEHA JOSHI
STJIT

2. CONTENTS
• Introduction
• Electrooculography
• Keywords
• Eye movements
• EOG detection
• BiDiM-EOG
• EOG signal filtering & acquision system
• Guidance of wheelchair
• Robotic movements
• Advantages & Disadvantages
• Conclusion

3. Introduction
• Eyes are our window to this large universe.
• It is estimated 150, 00 severely disabled persons able to
control only the muscles of their eyes without any problem.

4. Electrooculography(EOG)
• Electrooculography is a method for sensing eye movement
and is based on recording the standing corneal-retinal
potential (CRP) arising from hyperpolarization and
depolarization existing between the cornea and the retina;
this is commonly known as an electrooculogram.

5. keywords
• Depolarization
• Hyper polarization
• Corneal-Retinal Potential or
Electrooculographic potential
(ranges from 0.05 to 3.5 mV in human)

6. Eye Movements
– Four types of eye movements are
– Saccades (rapid simultaneous movement of both eyes in
same direction)
– Smooth pursuit movements (voluntary eye movement as if
they are following an object)
– Vergence movements(simultaneous movement of eye in
opposite direction)
– Vestibulo-ocular movements(stabilizes the eyes, relative to
the external world, thus compensating for the movements)

7. EOG detection
The EOG is captured by five electrodes(acts as transducer) placed
around the eyes
Horizontal Vertical
Reference

8. Contnd….

9. EOG Signals
• HEOG Signals: Obtained from horizontal eye
movements
• Eye movement: from centre to left: +ve voltage spike
from center to right:-ve voltage spike
• VEOG Signals: Obtained from vertical eye
movements
• Eye movement: from centre to top: +ve voltage spike
from centre to bottom: -ve voltage spike
• Blink Signals: Obtained due to blinking of eyes
• Voluntary Blink Signals
• Involuntary Blink Signals

10. Contnd…

11. EYE MODEL BASED ON EOG(BIDIM-EOG)
EOG
FILTER USER SAFETY
SACCADIC
MOVEMENTS
DETECTOR
POSITION
CONTROL
OUTPUT
CONTROL
SMOOTH
MOVEMENTS
DETECTOR
SPEED
CONTROL
FEEDBACK
PARAMETERS
ADJUSTMENT
OUTPUT

12. EOG signal filtering & acquision
system

13. HOW TO GUIDE A WHEELCHAIR WITH THE HELP OF EYE MOVEMENTS?
The EOG signal is recorded by Ag-Agcl electrode.
By means of a acquisition system , signals are sent to a PC, in which they are processed to calculate the
eye gaze.
The control commands are given to the wheelchair in order to reach the required destination.
There exists a visual feedback in the system by means of tactile screen
that the user has in front of him.

14. Eg: User wheelchair interface & Trajectory generated

15. Video demonstration

16. • Range
• Linearity
• Non-invasive
• Obstacles in front of the eye
• Cost effective
• Eye closure is permissible
• Real Time

17. In this work we present a system that can be used as a means
of control for allowing the handicapped , especially those with
only eye-motor coordination, to live more independent lives.
This project is a low cost assistive robotic wheel chair system
for disabled people. The total command control based on EOG
permits to wheel chair users to guide it with a enough degree of
comfort ability .