The document discusses eye movement tracking techniques for human-computer interaction. It describes the anatomy and physiology of the eye, how eye movements are tracked using different techniques like skin electrodes, contact lenses, head-mounted and remote systems. Challenges in eye tracking like the midas touch problem and jitter are also covered. Applications of eye tracking like accessibility, system enhancement and virtual displays are discussed. Case studies on using eye tracking for visual search tasks in cognitive science and on the Tobii T120 eye tracker are provided. The conclusion states that while eye tracking is not perfect, it has potential to provide new effective interaction methods.

1. EYE MOVEMENT BASED HUMAN COMPUTER INTERACTION
TECHNIQUES: TOWARDS NON-COMMAND INTERFACE
BY
RAJ KIRAN
09B91A0586
GNITC

2. The Eye
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Eyes are the windows of the soul.
 Eye are the parts which perceive light in our human
body.
 Interaction with other body parts.
 A Combination of eyes and brain help us in
processesing complex visual information.

3. How We See ?
Eye Movement Non-command
Introduction Conclusion
Tracking Interface

4. Physiology of Eye
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Cornea is a transparent structure that
covers the iris and pupil; a part of the
focusing system of an eye.
 Pupil is the adjustable opening at the
center of the iris that allows varying
amounts of light to enter the eye.
 Lens helps to focus light on the retina.
 Retina includes rods (94%), which are
sensitive to light and cones (6%) that
capture colors. Cones are
concentrated in the centre of the
retina - the fovea

5. Facts about Human gaze
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 One’s eye is rarely stationary.
 Eye movement reflects a viewer’s visual information
process.
 The eyes can move faster than the hand.
 Eye movement consists of:
 Saccades
 Fixations

6. Eye tracking Technology
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 What is Eye tracking?
 Eye tracking is the measurement
of eye activity.
 Why use eye tracking ?
 Gives an accurate measure of where one’s looking.
 Enhances or back-ups observations.
 Can lead to many potentially useful applications.

7. Techniques for measuring eye movements
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Measuring Visual line of gaze (Where he or she is looking in
space).
 Different techniques used for measuring eye movements.
 Skin Electrodes
 Contact lens
 Head Mounted
 Remote System

8. Techniques for eye tracking: Skin Electrodes
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Electrodes placed on the skin around the eye socket.
 Measuring the electrical differences between retina and
cornea.
 GOOD POINTS:
 Both eyes can be recorded together
 Least expensive
 Simple to use
 DOWNFALLS:
 It is limited to horizontal and vertical movements
 Poor accuracy for absolute positioning

9. Techniques for eye tracking: Contact lens
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 A non-slipping contact lens fits over corneal bulge.
 Tracking is recorded by affixing a magnetic coil or mirror to the
lens.
 GOOD POINTS:
 Provides accurate data about the
nature of human eye movements.
 DOWNFALLS:
 Extremely awkward, uncomfortable for the user.
 Interferes with blinking.
 Covers only a limited range of eye movements.

10. Techniques for eye tracking: Head Mounted
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Small camera and light source mounted to users head via a
headband or helmet
 Reports the angle of the user’s eye with respect to his or her
head.
 Two data sources can determine the line of gaze in physical
space.
 GOOD POINTS:
 Doesn’t restrict the user’s head movements
 DOWNFALLS:
 More awkward to use than the desk-based
system as the user has to have instrument
mounted to head.

11. Techniques for eye tracking: Remote System
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Most practical method of eye tracking.
 Uses Illuminator/eye camera.
 Tracking visible features of the eye.
 Head movements can be distinguished
from eye movements by tracking 2 points.
 GOOD POINTS:
 Allows for a fair range of head movements
 Accurate, fast and affordable
 DOWNFALLS:
 Head still needs to stay within camera range.
 Delicate to calibrate and operate

12. Current Challenges
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Midas Touch problem
 Jitter of eye
 Multiple “Fixations in a single Gaze”
 Instability in eye Tracking Equipment

13. Non-command Interface
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Non-command interaction
 Interaction Techniques
 Object Selection
 Moving an object
 Eye controlled scrolling text
 Menu commands
 Listener window

14. Towards and beyond Non-command interfaces
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Command Style
 Interactivity
 New Interface Styles
 Beyond Windows System

15. Interactive Applications
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Accessibility
 System Enhancement
 Non-Command Based Systems
 Virtual Displays

16. Interactive Applications: Accessibility
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Eye tracking can allow people to use their eyes to
communicate
 Because the ability of some handicapped individuals to
operate other devices is limited or nonexistent.
 The eye movement interface need to perform only
minimally well to provide a significant benefit.

17. Interactive Applications: Non-command based systems
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Non-command based system
 The system passively monitors the user and responds
as appropriate, rather than waiting for the user to issue
specific commands.
 EX : Gamming Applications

18. Interactive Applications: System Enhancement
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Mainly used for the users whose hands are occupied
 Potential Problems:
 Some will find the eye movement based interface better
(faster, more convenient and more natural) while others
may feel uncomfortable.
 Too unnatural to use in critical situations?
 Eye tracking may be best used to act as
a supplemental input or display method.

19. Interactive Applications: Virtual Displays
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Making VR more realistic
 If accurate, the user cannot detect the difference between
this arrangement and the large, high-resolution display it
emulates.

20. A Case Study on Tobii T120 Eye Tracker
Tobii T120 Eye Tracker
Tobii T120 Eye Trackers enable you to conduct on-screen
eye tracking studies for a wide variety of research purposes. It
delivers reliable results in a natural testing environment

21. A Case Study on Tobii T120 Eye Tracker
Figure : Overview Of Eye Tracking System

22. A Case Study on Tobii T120 Eye Tracker
Corneal reflection
Figure : Working of Eye Tracking System
 Initially position and orientation of eye are determined.
 The Gaze Point is found at the intersection of optical axis and
the viewing plane

23. A Case Study on Eye Tracking in Cognitive Science
Visual Search
 Physical and cognitive processing limitations can prevent us
from instantly recognizing the presence of a target item in a
single glance.

24. A Case Study on Eye Tracking in Cognitive Science
Method
Subjects had to look for a specific object within a visual scene.
 Target could be specified by a word or a picture. Pictures
specify the target template more elaborately than words.
 To manipulate the time that the subject had to build up a
target template and keep it salient in memory.
 To manipulate target familiarity, the target specification was
either shown 4 times to the subject prior to experiment.

25. A Case Study on Eye Tracking in Cognitive Science

26. A Case Study on Eye Tracking in Cognitive Science
Results
Picture rather than word resulted in:
 Faster total search times
 Shorter scanning and verification times
 Fewer regions visited
 Shorter scanning fixation durations (rejection of
distractors)

27. Conclusion
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 An Eye tracker as an input device is far from “perfect”
 The approach in designing interaction techniques should be
more efficient
 We can view eye movement-based interaction as an instance of
an emerging new style of user-computer interaction
 It is helpful for usability studies to understand users interact
with their environments
 Potentially could provide new and more effective methods of
computer-human interaction

28. Conclusion
Eye Movement Non-command
Introduction Conclusion
Tracking Interface
 Potentially could provide new and more effective methods of
computer-human interaction
 It is amazing that eye movement-based interaction can be done
at all
 The Technology is still improving, and is “not quite there” yet –
but has an exciting future!