EYETRACKING TECHNOLOGY

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EYE-TRACKINGTECHNOLOGY

• Humans, Computers and Cognition
• Alysen Espersen
• October 15th, 2002

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Facts About Human Gaze

• Ones eye is rarely stationary
• Eye movement reflects a viewers visual
  information process
• The eye can move faster than the hand
• Eye movement consists of
• Saccades
• Fixations

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Why Use Eye Tracking?

• Gives an accurate measure of where ones visual
  attention is directed
• Enhances or backs-up observations
• May reveal patterns which may become proof of
  effective or ineffective usability
• Can lead to many potentially useful applications

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Types of Eye Tracking

• Skin Electrodes
• Contact Lens
• Head Mounted
• Remote Systems
• (Desk or Computer-based)

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Types of Eye TrackingSkin Electrodes

• Electrodes placed on the skin around the eye
  socket
• Measures electrical differences the between the
  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

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Types of Eye TrackingContact Lens

• 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

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Types of Eye Tracking Head Mounted

• Small camera and light source mounted to users
  head via a headband or helmet
• Reports the angle of the users eye with respect
  to his or her head.
• Two data sources can determine the line of gaze
  in physical space.

• GOOD POINTS
• Doesnt restrict the users head movements
  (including locations away from the computer
  screen)
• DOWNFALLS
• More awkward to use than the desk-based system as
  the user has to have instrument mounted to head.

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Types of Eye TrackingRemote Systems

• 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
• Not intrusive
• DOWNFALLS
• Head still needs to stay within camera range.
• Delicate to calibrate and operate

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Processing Raw Data

• Data from eye tracking is too low level and
  voluminous for immediate interpretation.
• Software packages can combine data from eye
  tracking and interaction logs to produce a
  page-by-page reports.

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Pitfall of Using Eye Tracking Technologies

• Equipment is still quite intrusive
• Noisy
• Restricted head movements
• Requires more patience by user
• Fairly large pool of test subjects is needed
• User vision must be considered
• How can we tell if and what info. is really being
  processed?
• eye fixations provide measurement of visual
  interest but do not provide a measure of
  cognitive interest.
• Often viewed as a time-consuming methodology
  returning questionable benefits.

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Previous Research/Applications

• 2 Main Categories
• Interface Usability Studies
• Interactive Applications

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• Interface Usability Studies
• Overview

• Challenging of the controversial Scanpath
  Theory(Noton and Stark, 1971)
• The Scanpath Theory
• Argues that its improbable that the eye is
  controlled by specific features of a visual
  display
• Rejects the explanation that subjects are driven
  by habits
• Since Internet users are repeatedly exposed to
  certain visual displays of information, the Web
  is an ideal stimulus to test this theory.
• Many studies dispute the Scanpath Theory

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Interface Usability Studies

• Eye Tracking CAN
• Tell whether users are looking at the screen
• Tell whether users are reading or scanning.
• Learn the relative intensity of a users
  attention to various parts of a web page
• Determine whether a user is searching for a
  specific item
• Compare user scan patterns

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Interface Usability Studies

• Eye Tracking CANT
• Let you know whether users actually see
  something
• Prove that users didnt see something
• Determine why users are looking at something
• Test everybody

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• Interface Usability Studies

• Online News portal study done by Stanford
  University and The Poynter Institute in 2000

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Research Applications/Studies Online News
Portals

• by Stanford University and The Poynter Institute
  (2000)
• the first eyetracking study documenting the
  actual second-by-second behavior of users of
  online news sites
• Tracked what subjects read and their
  movementsfrom page to page.
• Used 67 subjects in two cities
• Subjects were readers of online news - people who
  visited news-related sites at least three times a
  week.
• Each screen was analyzed by
• Format (what layout elements attracted users)
• Topics
• Actions
• Time spent on page

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Research Applications/Studies Online News
Portals
The numbers superimposed over the pink blocks
show the order in which fixation clusters. Follow
the numbers and note the roaming pattern. The
dark "x" to the right of photo that indicates a
mouse click for calling up a hyperlinked story.
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Research Applications/Studies Online News
Portals
Return to main page after link click
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Research Applications/Studies Online News
Portals

• OVERALL CONCLUSIONS
• A strong preference for text over graphics
  (briefs or captions)
• The eyes of online news readers then come back to
  the photos and graphics
• Banner ads do catch online readers' attention
• for an average of one second.
• Long enough to perceive the ad (but what about
  animated ads?)
• Statistics of how different users (by age, sex)
  navigate through online news

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• Interactive Applications

• Accessibility
• System Enhancement
• Non-Command Based Systems
• Virtual Displays

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Interactive ApplicationsAccessibility

• Eye tracking can allow people to use their eyes
  to communicate
• Its users include people with brain injuries,
  cerebral palsy, multiple sclerosis, muscular
  dystrophy, spinal cord injuries, spinal muscular
  atrophy, strokes, etc.

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Interactive ApplicationsSystem Enhancement

• Aimed toward 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.

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Interactive ApplicationsNon-Command Based
Systems

• The computer passively monitors the user and
  responds as appropriate, rather than waiting for
  the user to issue specific commands.
• Eye-controlled paddleball game
• The Little Prince (interactive childrens story)
• The user controls the flow of the narration by
  where he or she looks without explicit commands
  (interactive fiction)
• Problem How can we issue a command clearly?
• Gaze duration and blnking can be ineffective or
  faulty

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Interactive ApplicationsVirtual Displays

• Making VR more realistic
• If accurate, the user cannot detect the
  difference between this arrangement and the
  large, high-resolution display it emulates.

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Advantages of Using Eye Trackingas an Input
Device

• Eye movement is faster than other current input
  media
• No training or particular coordination is
  required of normal users
• Can determine where the users interest is
  focused automatically

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Disadvantages of Using Eye Trackingas an Input
Device

• People are not accustomed to operating devices by
  simply moving their eyes.
• In interactive applications, using the eye as an
  input device, when does the system decide that a
  user is interested in a visual object?

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Future of Eye tracking?

• Helpful for usability studies to understand users
  interact with their environments.
• Potentially could provide new and more effective
  methods of computer-human interaction.
• Eye tracking equipment is still improving, and is
  not quite there yet but has an exciting
  future!

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VIDEOS
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VIDEOS
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VIDEOS
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LinksRESEARCH LINKS

• Gaze-Based Interaction Group
• http//www.cs.uta.fi/research/hci/gaze/links.php
• A page of links about various eye tracking
  projects and research studies
• User Interface Engineering
• http//world.std.com/7Euieweb/index.html
• Stanford Poynter Project
• http//www.poynter.org/eyetrack2000/index.htm
• Critique on Study http//www.poynter.org/centerp
  iece/071200alan.htm
• Technology News New Software Replaces Computer
  Keyboards with Eyes August 23,
  2002http//www3.cosmiverse.com/news/tech/0802/tec
  h08230201.html
• An interesting article on a software has been
  named "Dasher", that claims to "exploit our eyes'
  natural ability to navigate and identify familiar
  patterns. It is the result of work done by a team
  at Cavendish Laboratory in Cambridge, UK. An
  eye-tracking device allows users to select
  letters from the screen.
• The Little Prince (interactive childrens story
  experiment)
• I. Starker and R.A. Bolt, A Gaze-Responsive
  Self-Disclosing Display, Proc. ACM CHI 90 Human
  Factors in Computing Systems Conference pp. 3-9,
  Addison-Wesley/ACM Press (1990).

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Links ANALYSIS SOFTWARE

• SensoMotoric Instruments
• http//www.smi.de/specializes in the development
  and integration of eye movement measuring and
  evaluation systems
• Seeing Machines
• http//www.seeingmachines.com/products.htm
• Creators of faceLAB -a head, face and gaze
  tracking technology that measures the position of
  a human head, gaze direction and blink events.
• GazeTracker
• http//www.a-s-l.com/gazetracker.htm
• Software that consolidates the information that
  researchers need to conduct their web design and
  software usability studies into one piece of
  software.
• EYETECH DIGITAL SYSTEMS, INC.
• http//www.eyetechds.com/
• Software to operate your PC hands free
• ARRINGTON RESEARCH, INC.
• http//www.arringtonresearch.com/
• -creators of eye tracking hardware and software

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Links EYE TRACKING EQUIPMENT

• Eye Movement Equipment Database (EMED)
• http//ibs.derby.ac.uk/emed/
• Eye Movement Equipment Database, based in the
  Institute of Behavioural Sciences, University of
  Derby.
• LC Technologies
• http//www.eyegaze.com/
• LC Technologies designs, manufactures, and
  distributes unobtrusive video eyetracking
  systems.
• Metrovision
• http//www.metrovision.fr/
• A company located in France that sells
  instruments for ophthalmologists including visual
  field, visual electrophysiology, contrast
  sensitivity, and eye movements.
• Applied Science Laboratories
• http//www.a-s-l.com/index.htm
• develops eye tracking technology and systems
• SR Research
• http//www.eyelinkinfo.com/
• Creators of EyeLink II an eye tracking system
  that consists of three miniature cameras mounted
  on a comfortable leather-padded.

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Bibliography

• Crowe, Eric C. and Narayanan, Hari. Comparing
  interfaces based on what users watch and do. In
  Proceedings of Eye Tracking Research
  Applications Symposium 2000, pages 29 -- 36. ACM,
  2000.
• Hayhoe, Mary M. , Ballard,Dana H., Triesch,
  Jochen, Shinoda, Hiroyuki, Aivar, Pilar, and
  Sullivan, Brian. Vision in Natural and Virtual
  Environments. In Proceedings of Eye Tracking
  Research Applications Symposium 2002, pages 7
  -- 13. ACM, 2002.
• Jacob. Robert J.K., "Eye Tracking in Advanced
  Interface Design," HCI Lab, Naval Research
  Laboratory http//www.eecs.tufts.edu/jacob/papers
  /barfield.html
• Josephson, Sheree (Weber State University, USA)
  and Holmes, Michael E. (Ball State University).
  Visual Attention to Repeated Internet Images
  Testing the Scanpath Theory on the World Wide
  Web. In Proceedings of Eye Tracking Research
  Applications Symposium 2002, pages 43 -- 49. ACM,
  2002.
• Description of a study that challenges the
  Scanpath Theory, concluding that other forces
  such as visual features or memory may be of
  importance.
• Lewenstein, M., Edwards, G., Tatar, D., and
  DeVigal, A. Stanford-Poynter Project. See
  http//www.poynter.org/eyetrack2000/index.htm.
  2000.
• Schroeder, W. (1998, September/October). What Is
  Eye Tracking Good for? User Interface
  Engineering. On-Line Available URL
  http//world.std.com/uieweb/eyetrack2.htm
• Schroeder, W. (1998, September/October). Testing
  web sites with eye-tracking. User Interface
  Engineering. On-Line Available URL
  http//world.std.com/uieweb/eyetrack1.htm
• Vertegall, Roel. Designing Attentive
  Interfaces. In Proceedings of Eye Tracking
  Research Applications Symposium 2002, pages 23
  -- 30. ACM, 2002.