Eye Tracking

Wednesday, 2 May 2007

References

http://www.cogain.org/glossary/115
http://e-collection.ethbib.ethz.ch/ecol-pool/bericht/bericht_21.pdf - Study in to eye tracking involving cats
http://www.useit.com/alertbox/reading_pattern.html - Study into eye tracking performed recently
http://www.cs.cmu.edu/~sfussell/pubs/Manuscripts/Eye-tracking03.pdf - Eye tracking and health study
http://www.mis.coventry.ac.uk/~pevery/306is/T6/stars/eyetracking.html Disavans of eye track
http://www.webaim.org/articles/motor/assistive.php#eyetracking - For eye tracking devices
http://www.uxmatters.com/MT/archives/000040.php Seing Through Your Users' Eyes
http://www.pervasive.dk/ Information on Pervasive computing
http://66.102.9.104/search?q=cache:yWMZiUt0ZxcJ:iat.ubalt.edu/courses/old/idia750.185_F02/alysenEspersen.ppt+%22advantages+of+using+eye+tracking%22&hl=en&ct=clnk&cd=2&gl=uk used to gather information of the advantages of eye tracking

Video Clips

There are two videos that show examples of eye tracking in use:

Eye tracking is a scientific method used in fields of research involving psychology and cognitive science to track the movement of subjects' eyes using an infra-red analysis of the subject's face, eyeballs, and corneal reflex.

The eye tracking device made by Swedish company Tobii that is used in these usability surveys is not like the conventional types of eye camera used that are fitted to the body, but rather, this contact-less eye tracker is built into a liquid crystal display, and is the optimal tool for conducting Web usability surveys using monitors. With this device even used in psychological studies of infants and for early childhood education, it can be used irrespective of the subject's age, skills or literacy level.

Point 2 Surveying usability based on the principles of the user-oriented design process. Even when the same user is viewing the same Web screen, their line of vision will differ completely depending on the circumstances they are viewing that site in each time. The will look at things in a different order and focus on different points depending on whether they are busy and just need to find the information they need, or whether they are just browsing the site when they have spare time.

Just as “build the context of use” is set out at the beginning of the design process defined under ISO13407, the international standard for human-centered design, if usability surveys are conducted without ascertaining the circumstances surrounding that user, any issues will not be accurately identified. No matter what sort of sophisticated tool you use in this case, the surveys are not likely to yield any meaningful results.

With this service, however, specialist analysts with knowledge of the user-oriented design process select subjects that correspond with the purpose of the site and target user needs, and design, administer, analyze, and report on tests to accurately identify any areas where usability could be improved.

Point 3 Identify problems more accurately by combining eye tracking with user tests. Cognitive psychology studies report on the existence of central and peripheral human consciousness. For example, sometimes you will be concentrating on something or thinking about something on your way home from work, so much so that when you get home, you cannot recall what roads you took to get home. In this case, your peripheral consciousness was telling you that the lights are green and that there are no dangers on the road.

When users browse websites too, the movement of their line of vision does not necessarily correspond with their central consciousness. This is because sometimes the user might be focusing on a particular point, but thinking about something else entirely.

With this service, eye tracking surveys and user tests can be used together to clarify this gap between the user's vision and their consciousness, so as to enable issues to be more accurately identified. These tests can also be used in conjunction with access log analysis for surveying existing sites.

Usage Scenarios

To assess the usability of sites with purchasing or reservation functions that involves a lot of user interaction.

To provide user assessments of the information design on information sites and news sites that span a broad range of content categories.

To assess the user interfaces on pages needed to guide users to content on the site, such as the top page or category indexes.

Service Options

a. Usability surveys using eye tracking analysis.

With this service, user tests combined with eye tracking surveys can be used to investigate and analyze problems with existing websites. Problems and issues associated with Web usability can be identified by shedding some light on the gap between what the existing site offers and how users use the site and what their needs are.

b. Design evaluation through eye tracking analysis during the website construction phase.

This service builds an evaluation of website design against user requirements through eye tracking analysis into the design process during website construction. Subsequent design revisions, as provided for in the ISO13407-based human-centered design process mean that the results of user tests can be used as design feedback so as to enhance site usability.

Flow of Service Procedures

a. Usability surveys using eye tracking analysis.

This service covers everything from test design to implementation and reporting.

Interviews

Define requirements, contract

Test design

Testing of current site

Analysis Reporting.

b. UI evaluation through eye tracking analysis during the Web design process User tests are conducted during the design phase of website construction. The results of these tests are provided as design feedback to enhance site usability of requirements, contract (construction).

Disadvantages of Eye Tracking

The equipment is expensive
Some users can't work with the equipment (for example if they wear contact lenses or have long eye lashes)
Calibrating the equipment takes time; this problem may resultantly cause the user to deviate from using the device.

Point elaboration -

Point 1 - It’s not cheap to outfit a lab with a decent eyetracker. Even Google, which has all the money in the world, has only outfitted one of their many labs. In addition to the money spent on the equipment, you have to spend money training people how to use it, which is not a cheap proposition.

Point 2 - not every participant can work with an eyetracker. Depending on the hardware, people with a variety of attributes automatically are disqualified from eyetracking. Everything from contact lenses to long eye lashes can get in the way of the device working properly.

Point 3 - Getting a participant set up and calibrated with the device can take time away causing a lack of interest in using the device.

Point 4 - Eye movements, like other passive and non-command inputs are often non-intentional, so they must be interpreted carefully to avoid unwanted responses to user actions. In terms of eye movement, we call this the "Midas Touch" problem. The problem of employing the use of an eye tracker interface is that people are not accustomed to operating devices simply by moving their eyes.

Point 5 - A major disadvantage is that the eye as a computer input device. Moving one's eyes is often an almost subconscious act. Unlike a mouse, it is relatively difficult to control eye position consciously and precisely at all times. Instability is introduced into the output of the eye tracker whenever it fails to obtain an adequate video image of the eye for one or more frames. This could mean that the user blinked or moved his or her head outside the tracked region.

Point 6 - As eye movements are so different from conventional computer inputs, we achieve best results with a philosophy that tries, as much as possible, to use natural eye movements as an implicit input, rather than to train a user to move the eyes in a particular way to operate the system.

Advantages of Eye Tracking and Usability

There are many types of advantages of using eye tracking.

Eye Tracking adds detailed, quantitative data to the usability testing process. We are no longer limited to just general measures (e.g. success rate, errors) or subjective feedback (e.g. comments and ratings). Rather, we can pair traditional usability findings with Eye Tracking data to gain a fuller understanding of the effectiveness of an interface's design and content. (Source: http://www.electronicink.com/think)

This type of technology will have a big impact in computing. The research above will allow users to effectively research on what areas people focus. This can help when developing websites or displaying information.

Eye tracking is a valuable yet cost-effective addition to any usability testing and compliments task-based observation methods well. (Source: http://www.simpleusability.com/services/usability/eye-tracking)

Advantages:

Eye movement is faster than other current input media
No training or particular coordination is required of normal users
Can determine where the user’s interest is focused automatically
Helpful for usability studies to understand users interact with their environments

Potential Applications

Eye gaze correction for videoconferencing
Maximizing controllers’ efficiency, minimizing dangers in air traffic displays
Developing video games and graphics
Marketing research and E-commerce website development
Potentially could provide new and more effective methods of computer-human interaction.

Eye Tracking can tell whether users are looking at the screen, reading information or scanning information. It can also show the intensity of the user’s attention and can determine whether a user is searching for specific information.

if we intend to tell more about advantages we can add:

Easy

Very quick set up. No complicated hardware to configure, simply install the PCI card in your computer and load the software
Intuitive user interface
Real-time feedback of eye movement data
The Auto-threshold feature quickly provides luminance threshold values for discriminating both the pupil and glint automatically
No calibration is required for many applications
Easy Slip Correction feature and re-presentation of stray calibration points
Automatic blink detection and suppression
The powerful SDK makes it very easy to interface eye tracking with your other applications
SlideShow -- super-easy stimulus presentation for experiments
Intuitive graphical analysis of data with fixation-time representation

Flexible

Select between 30 Hz and 60 Hz operation modes
Robust against different lighting conditions
Pupil-only tracking, Glint-only tracking, or choose Pupil-Glint Vector tracking that provides tolerance to head movements
Choose between Dark Pupil or Bright Pupil tracking
Run ViewPoint on the same computer as your stimulus presentation or on a remote computer
Real-time interface between the computer running ViewPoint and other computers (PC or Mac) provides maximum flexibility
Software Developers Kit provides complete external control of ViewPoint
Visual Range +/- 44° of visual arc horizontal and +/- 20° vertical

Eye Tracking: An Assistive Technology

The development of eye tracking systems have allowed for the creation of an assistive technology which can aid users with special needs in performing tasks on a computer. The following is an example of an eye tracking assistive technology:

VisionKey

VisionKey combines a viewer mounted on a pair of standard frames with a small control unit. An eye tracker and a microcomputer measure the position of the eye and when a selection is made, it appears on the control unit LCD and on the computer. Users look at a specific word, letter or character on the chart in front of their eye and "type" by holding their gaze until a selection is confirmed by a green highlight and a beep.

More Detailed Description

Eye tracking devices can be a powerful alternative for individuals with no control, or only limited control, over their hand movements. The device follows the movement of the eyes and allows the person to navigate through the web with only eye movements. Special software allows the person to type, and may include word-completion technology to speed up the process. These systems can be expensive—usually in the thousands of US dollars—so they are less common than the less sophisticated devices, such as mouth sticks and head wands.

What is Eye Tracking?

Eye tracking means figuring out the movement of eye as a person is looking at something. Video-based eye tracking devices observe a person's pupil to determine the direction of their gaze. Eye-tracking can be used for input, by directly controlling a pointer on the screen, or even for communicating the gaze direction to a co-worker looking at the same document (much like a telepointer). Eye-tracking can also be used to study how user interfaces are being used and may give insight into screen layout issues and how users are performing their tasks. Note: Eye Tracking can also refer to the ability of the eyes to smoothly and effortlessly follow a moving target (in vision research).

The following researched graphs show the difference between male and female eye tracking.

Source:http://www.eye-square.com/documents/EyeTracking-ResearchApplications.pdf From the source above usability testing was conducted to see the difference patterns between male and female.

As you can see in graph 1 the focus time spent by a female for texture information is far greater then a male. The male tend to focus more time on pictures.
Graph 2 shows how both male and female rate information. Females believe images are more important yet their focus eye tracking is fixed on text and male believe text is more important yet their focused eye tracking is fixed on images.