Oculograghy Ppt

Electrooculography Guidance of a Wheelchair Using Eye Movement Codification

Presented By,

K. Uday Sravanth

M. Srikanth

CVR College of Engineering

EIE 3rd year

Introduction Electro- Oculography Working Guidance Interfacing Advantages & Disadvantages Conclusion

Agenda

Assistive robotics can improve the quality of life for disable people.

This paper reports work in the development of a robotic wheelchair system based in electrooculography.

However, a robotic wheelchair must interact with its user making the robotic system semi autonomous rather then complete autonomous.

Our system allows the users to tell the robot where to move in gross terms and will then carry out navigational tasks.

Introduction

A method of recording eye position and eye movement.

What is oculography?

What is electro-oculography? A measurement of retinal function by recording changes in steady,

resting electric potentials of the eye with electrodes placed near canthi . Useful in studies of eye movements and retinal functions.

EOG is the record of polarization potential commonly known as electrooculogram ranging from 0.05 to 3.5mV in humans and is linearly proportional to eye displacement.

These analog signals forms the oculographic measurements which are suitable for control purposes.

The human eye is an electric dipole with a negative pole at the fundus and a positive pole at the cornea.

The EOG signal is a result of a number of factors.

Electro-oculographic Potential

Electrode Placement & Factors

• Eyeball rotation.

• Eyelid movement.

• Head movements.

• Influence of the luminance.

In this paper the eye model used is Bidimensional bipolar model.

This model mainly concentrates on:

1). User safety

2). Saccade movements detection

3). Smooth movements detection

Eye Model Based In EOG

Results of Eye Gaze Angle

The aim of this control system is to guide an autonomous mobile robot using the positioning of the eye into its orbit by means of EOG signal.

The EOG signal is recorded using Ag - AgCl electrodes.

Guidance of Wheelchair Using EOG

The user has to do an eye movement (a “tick”) to select among the different commands presented in the screen

The actions are validated by time, this is, when a command is selected, if other “tick” is not generated during a time interval, the command is validated and the guidance action is executed.

The Robot Movements (guidance)

The guidance based on ocular commands has different options, such as continuous guidance, on off activation commands and tracking of the direction of the eye gaze.

This system mainly controls:

1). Linear Speed (Accelerator)

2). Angular Speed (Wheel)

Continuous Control Technique

1). UP : Linear speed increase (V++).

2). DOWN : Linear speed decrease (V--).

3). RIGHT : Angular speed increase (W++).

4). LEFT : Angular speed decrease (W--).

State machine

Trajectory , EOG Signal , Guidance Speed

Trajectory

Eye movements require minimum effort and allow direct selection techniques.

The total command control based on EOG permits the wheelchair users to guide it with a enough degree of comfort ability.

This wheelchair is restricted to a location Increase in time response due to time validation

required for the execution of command

Advantages & Disadvantages

This research project is aimed towards developing a usable, low-cost assistive robotic wheel chair system for disabled people.

Thus we here present a means of control allowing the handicapped, especially those with only eye-motor coordination, to live more independent lives.

Conclusion

Guidance of a wheelchair using electrooculography. Proceeding of the 3rd IMACS International Multi conference on Circuits, Systems, Communications and Computers.

http://ieeexplore.ieee.org/Xplore/guesthome.jsp?reload=true

http://dictionary.webmd.com/terms/electrooculography(eog)

http://en.scientificcommons.org/42622312

References

Queries

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