Introduction

Eye-gaze as a form of human machine interface holds great promise for improving the way we interact with machines. Eye-gaze tracking devices that are non-contact, non-restrictive, accurate and easy to use will increase the appeal for including eye-gaze information in future applications. The system we have developed and which we describe in this paper achieves these goals using a single high resolution camera with a fixed field of view. The single camera system has no moving parts which results in rapid reacquisition of the eye after loss of tracking. Free head motion is achieved using multiple glints and 3D modeling techniques. Accuracies of under 1° of visual angle are achieved over a field of view of 14x12x20 cm and over various hardware configurations, camera resolutions and frame rates.

1.1Eye Gaze Tracking Under Natural Head Movements

Most available remote eye gaze trackers based on Pupil Center Corneal Reaction (PCCR) technique have two characteristics that prevent them from being widely used as an important computer input device for human computer interaction. First, they must often be calibrated repeatedly for each individual; second, they have low tolerance for head movements and require the user to hold the head uncomfortably still. In this paper, we propose a novel solution for the classical PCCR technique that will simplify the calibration procedure and allow free head movements. The core of our method is to analytically obtain a head mapping function to compensate head movement. Specifically, the head mapping function allows to automatically map the eye movement measurement under an arbitrary head position to a reference head position so that the gaze can be estimated from the mapped eye measurement with respect to the reference head position. Furthermore, our method minimizes the calibration procedure to only one time for each individual. Our proposed method will significantly improve the usability of the eye gaze tracking technology, which is a major step for eye tracker to be accepted as a natural computer input device.

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Eye Gaze is defined as the line of sight of a person. It represents a person’s focus of attention. Eye gaze tracking has been an active research topic for many decades because of its potential usages in various applications such as Human Computer Interaction, Eye Disease Diagnosis, Human Behavior Study, etc. Earlier eye gaze trackers were fairly intrusive in that they require physical contacts with the user, such as placing a reactive white dot directly onto the eye or attaching a number of electrodes around the eye. Except the intrusive properties, most of these technologies also require the viewer’s head to be motionless during eye tracking. With the rapid technological advancements in both video cameras and microcomputers, eye gaze tracking technology based on the digital video analysis of eye movements has been widely explored.

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CHAPTER 2

INTRODUCTION

2.1 Introduction

The Eyegaze System is a communication and control system for people with

complex physical disabilities. You run the system with your eyes. By looking

at control keys displayed on a screen, a person can synthesize speech, control

his environment (lights, appliances, etc.), type, operate a telephone, run

computer software, operate a computer mouse, and access the Internet and e-

mail. Eyegaze Systems are being used to write books, attend school and

enhance the quality of life of people with disabilities all over the world.

Imagine yourself being a intelligent, motivated, and working person in the

fiercely competitive market of information technology, but just one problem

You can't use your hands. Or you can't speak. How do you do your job? How

do you stay employed? You can, because of a very good gift from computer

Industry : The Eyegaze, a communication & control system you run with

your eyes.

The Eyegaze System is a direct-select vision-controlled communication and

control system. It was developed in Fairfax, Virginia, by LC Technologies,

Inc.,

2.2 Block Diagram:

3

Figure: Block Diagram of Eyegaze System

4

CHAPTER 3

THE SKILLS NEEDED BY THE USER

This system is mainly developed for those who lack the use of their hands or

voice. Only requirements to operate the Eyegaze are control of at least one eye

with good vision & ability to keep head fairly still. Eyegaze Systems are in

use around the world.  Its users are adults and children with cerebral palsy,

spinal cord injuries, brain injuries, ALS, multiple sclerosis, brainstem strokes,

muscular dystrophy, and Werdnig-Hoffman syndrome.  Eyegaze Systems are

being used in homes, offices, schools, hospitals, and long-term care facilities.

By looking at control keys displayed on a screen, a person can synthesize

speech, control his environment (lights, appliances, etc.), type, operate a

telephone, run computer software, operate a computer mouse, and access the

Internet and e-mail. Eyegaze Systems are being used to write books, attend

school and enhance the quality of life of people with disabilities all over the

world.

5

Figure: An example of fixations and saccades over text. This is the typical pattern of eye movement during reading. The eyes never move smoothly

over still text.

3.1 Good control of one eye:

The user must be able to look up, down, left and right. He must be able to fix

his gaze on all areas of a 15-inch screen that is about 24 inches in front of his

face. He must be able to focus on one spot for at least 1/2 second.

Several common eye movement problems may interfere with Eyegaze use.

These include:

Nystagmus (constant, involuntary movement of the eyeball):

The user may not be able to fix his gaze long enough to make eyegaze

selections.

Alternating strabismus (eyes cannot be directed to the same object, either one

deviates):

6

The Eyegaze System is constantly tracking the same single eye. If, for

example, a user with alternating strabismus is operating the Eyegaze System

with the right eye, and that eye begins to deviate, the left eye will take over

and focus on the screen. The Eyegaze camera, however, will continue to take

pictures of the right eye, and the System will not be able to determine where

the user's left eye is focused. When the left eye deviates and the right eye is

again fixed on the screen the Eyegaze System will resume predicting the

gazepoint. Putting a partial eye patch over the nasal side of the eye not being

observed by the camera often solves this tracking problem. Since only the

unpatched eye can the screen, it will continuously focus on the screen. By

applying only a nasal-side patch to the other eye, the user will retain

peripheral vision on that side.

3.2 Adequate vision:

Several common vision problems may affect a user's ability to see text clearly

on the Eyegaze monitor. These include the following:

Inadequate Visual acuity:

The user must be able to see text on the screen clearly. If, prior to his injury or

the onset of his illness he wore glasses, he may need corrective lenses to

operate the Eyegaze System. If he's over 40 years old and has not had his

vision checked recently, he might need reading glasses in order to see the

screen clearly.

In most cases, eyetracking works well with glasses. The calibration procedure

accommodates for the refractive properties of most lenses. Hard-line bifocals

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can be a problem if the lens boundary splits the image of the pupil, making it

difficult for the system's image processing software to determine the pupil

center accurately. Graded bifocals, however, typically do not interfere with

eyetracking.

Soft contact lenses that cover all or most of the cornea generally work well

with the Eyegaze System. The corneal reflection is obtained from the contact

lens surface rather than the cornea itself. Small, hard contacts can interfere, if

the lens moves around considerably on the cornea and causes the corneal

reflection to move across the discontinuity between the contact lens and the

cornea.

Diplopia (double vision):

Diplopia may be the result of an injury to the brain, or a side effect of many

commonly prescribed medications, and may make it difficult for the user to

fix his gaze on a given point. Partially patching the eye not being tracked may

alleviate double vision during Eyegaze System operation.

Blurred vision:

Another occurrence associated with some brain injuries, as well as a side

effect of medications, a blurred image on the screen decreases the accuracy of

eye fixations.

Cataracts (clouding of the lens of the eye):

If a cataract has formed on the portion of the lens that covers the pupil, it may

prevent light from passing through the pupil to reflect off the retina. Without a

good retinal reflection the Eyegaze System cannot accurately predict the user's

eye fixations. The clouded lens may also make it difficult for a user to see text

8

on the screen clearly. Surgical removal of the cataracts will normally solve the

problem and make Eyegaze use possible.

Homonymous hemianopsia (blindness or defective vision in the right or left

halves of the visual fields of both eyes):

This may make calibration almost impossible if the user cannot see calibration

points on one side of the screen.

3.3 Ability to maintain a position in front of the Eyegaze monitor:

It is generally easiest to run the System from an upright, seated position, with

the head centered in front of the Eyegaze monitor. However the Eyegaze

System can be operated from a semi-reclined position if necessary.

Continuous, uncontrolled head movement can make Eyegaze operation

difficult, since the Eyegaze System must relocate the eye each time the user

moves away from the camera's field of view and then returns. Even though the

System's eye search is completed in just a second or two, it will be more tiring

for a user with constant head movement to operate the System.

Absence of medication side effects that affect Eyegaze operation:

Many commonly prescribed medications have potential side effects that can

make it difficult to operate Eyegaze. Anticonvulsants (seizure drugs) can

cause: nystagmus, blurred vision, diplopia, dizziness, drowsiness, headache

and confusion. Some antidepressants can cause blurred vision and mydriasis

(abnormally dilated pupil.) And Baclofen, a drug commonly used to decrease

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muscle spasms, can cause dizziness, drowsiness, headache, disorientation,

blurred vision and mydriasis. Mydriasis can be severe enough to block

eyetracking. If the retinal reflection is extremely bright, and the corneal

reflection is sitting on top of a big, bright pupil, the corneal reflection may be

indistinguishable and therefore unreadable by the computer.

3.4 Mental abilities that improve the probability for successful Eyegaze use:

Cognition:

Cognitive level may be difficult to assess in someone who is locked in,

especially if a rudimentary communication system has not been established. In

general, a user with average intelligence will best maximize the capabilities of

an Eyegaze System.

Ability to read:

At present, the Eyegaze System is configured for users who are literate. The

System is text-based. A young child with average intelligence may not be

reading yet, but probably has the capability to learn to read at an average age.

He may be able to recognize words, and may be moving his eyes in a left to

right pattern in preparation for reading. As an interim solution many teachers

and parents stick pictures directly onto the screen. When the child looks at the

picture he activates the Eyegaze key that is located directly underneath it.

Memory:

10

Memory deficits are a particular concern in considering the Eyegaze System

for someone with a brain injury. A user who can't remember from one day to

the next how to operate the system may find it too difficult to use effectively.

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CHAPTER 4

HOW DOES THE EYEGAZE SYSTEM WORK

For using the Eyegaze Systems the users sits in front of the system’s screen

and for tracking the eye movement of the user the systems follows the below

mentioned steps. As the system starts tracking the movement of the eyes, all

the features of the system can be used depending on the requirements. As a

user sits in front of the Eyegaze monitor, a specialized video camera mounted

below the monitor observes one of the user's eyes.  Sophisticated image-

processing software in the Eyegaze System's computer continually analyzes

the video image of the eye and determines where the user is looking on the

screen.  Nothing is attached to the user's head or body.

Figure: Eyegaze System Application

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1. As a user sits in front of the Eyegaze monitor, a specialized video camera mounted below the monitor observes one of the user's eyes.

2. Sophisticated image processing software in the Eyegaze System's computer continually analyzes the video image of the eye and determines where the user is looking on the screen. Nothing actually is attached to the user's head or body.

3. The Eyegaze System uses the pupil-center/corneal-reflection method to determine where the user is looking on the screen. An infrared-sensitive video camera, mounted beneath the System's monitor, takes 60 pictures per second of the user's eye.

4. A low power, infrared light emitting diode (LED), mounted in the center of the camera's lens illuminates the eye. The LED reflects a small bit of light off the surface of the eye's cornea. The light also shines through the pupil and reflects off of the retina, the back surface of the eye, and causes the pupil to appear white. The bright-pupil effect enhances the camera's image of the pupil and makes it easier for the image processing functions to locate the center of the pupil.

5. The computer calculates the person's gaze point, i.e., the coordinates of where he is looking on the screen, based on the relative positions of the pupil center and corneal reflection within the video image of the eye.

6. Typically the Eyegaze System predicts the gaze point with an average accuracy of a quarter inch or better.

7. Prior to operating the eye tracking applications, the Eyegaze System must learn several physiological properties of a user's eye in order to be able to project his gazepoint accurately. The system learns these properties by performing a calibration procedure.

13

8. The user calibrates the system by fixing his gaze on a small yellow circle displayed on the screen, and following it as it moves around the screen. The calibration procedure usually takes about 15 seconds, and the user does not need to recalibrate if he moves away from the Eyegaze System and returns later.

9. A user operates the Eyegaze System by looking at rectangular keys that are displayed on the control screen. To "press" an Eyegaze key, the user looks at the key for a specified period of time.

10.The gaze duration required to visually activate a key, typically a fraction of a second, is adjustable. An array of menu keys and exit keys allow the user to navigate around the Eyegaze programs independently.

In detail the procedure can be described as follows: The Eyegaze System uses

the pupil-center/corneal-reflection method to determine where the user is

looking on the screen. An infrared-sensitive video camera, mounted beneath

the System's monitor, takes 60 pictures per second of the user's eye. A low

power, infrared light emitting diode (LED), mounted in the center of the

camera's lens illuminates the eye. The LED reflects a small bit of light off the

surface of the eye's cornea. The light also shines through the pupil and reflects

off of the retina, the back surface of the eye, and causes the pupil to appear

white. The bright-pupil effect enhances the camera's image of the pupil and

makes it easier for the image processing functions to locate the center of the

pupil

The computer calculates the person's gazepoint, i.e., the coordinates of where

he is looking on the screen, based on the relative positions of the pupil center

and corneal reflection within the video image of the eye. Typically the

Eyegaze System predicts the gazepoint with an average accuracy of a quarter

inch or better.

14

Prior to operating the eyetracking applications, the Eyegaze System must

learn several physiological properties of a user's eye in order to be able to

project his gazepoint accurately. The system learns these properties by

performing a calibration procedure. The user calibrates the system by fixing

his gaze on a small yellow circle displayed on the screen, and following it as it

moves around the screen. The calibration procedure usually takes about 15

seconds, and the user does not need to recalibrate if he moves away from the

Eyegaze System and returns later.

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CHAPTER 5

HOW TO RUN THE EYEGAZE SYSTEM

A user operates the Eyegaze System by looking at rectangular keys that are displayed on

the control screen. To "press" an Eyegaze key, the user looks at the key for a specified

period of time.  The gaze duration required to visually activate a key, typically a fraction of

a second, is adjustable.  An array of menu keys and exit keys allow the user to navigate

around the Eyegaze programs independently.

The Edge Analysis System uses the Pupil-Center/Corneal-Reflection method to determine the eye's gaze direction.

A video camera located below the computer screen remotely and unobtrusively observes the subject's eye.

No attachments to the head are required. A small, low power, infrared light emitting diode (LED) located at the

center of the camera lens illuminates the eye. The LED generates the corneal reflection and causes the bright pupil effect, which enhances the camera's image of the pupil.

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CHAPTER 6

USES OF EYEGAZE

Every year more than 100 000 people are diagnosed with motor neurone

diseases. Typically, even when all other ways of communicating are either

severely damaged or completely lost, the eyes still function. Communication

by Gaze Interaction (COGAIN) is a Network of Excellence designed

specifically to help people with these disabilities to communicate more

effectively with eye gaze. At the COGAIN stand you can see how this

technology is used by a person who relies on it.

Current eye tracking equipment allows users to generate text on a computer by

using eye gaze. Users are able to select letters and numbers by looking at a

keyboard on a screen with their eyes, and can construct words and sentences

that can be spoken aloud by the system. Using these systems both empowers

and enables people with disabilities as they can now communicate without the

need for an assistant or helper, giving the users greater freedom in their lives.

Eye tracking systems that allow text entry by eye gaze have been in existence

for about two decades, but the technology is still only available to a small

portion of the potential user population. Obstacles for more wide-spread use

currently include: the high cost of eye tracking equipment, the limitation that

gaze communication applications may only work with a particular dedicated

eye tracking device, and finally that eye tracking

devices are often hard to use and require experts to operate them.

6.1 The Basic Eyegaze Can:

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ADJUST TO A NEW USER in about 15 seconds. (Calibration)

TYPE with one of four keyboards, then print or speak. (Typewriter)

TURN pages on the computer screen by looking at "up" or "down". (Read

Text)

PLAY games, two "Paddle" games, plus Solitaire and Slot Machine. (Games)

TEACH new users with simplified screens. (Teach Screens)

6.2 With Options The Eyegaze Can:

BE AT TWO SITES!! Portable computer has a handle to hand-carry between

two sites. Two sets of other components and cables for access to Eyegaze

System at school, work or home. Dimensions 9"x5'txl7'1, weight

approximately 16 lbs. (Transportable Computer)

BE A KEYBOARD to a second computer to run any keyboard-controlled

software, by means of the T-TAM connector. (Second Computer Mode)

SPEAK 100 "canned phrases" through a speech synthesizer, with a single

glance of the eye. Phrases can be changed by caregiver or user. (Phrases)

CONTROL appliances anywhere in the home or office from one Eyegaze

screen. No special wiring. (Lights and Appliances)

DIAL and answer a speaker phone from one screen. "Phone Book" stores 16

frequently used numbers. (Telephone)

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CHAPTER 7

MENUS OF EYEGAZE SYSTEM

The Main Menu:

The Main Menu appears on the screen as soon as the user completes a 15-

second calibration procedure. The Main Menu presents a list of available

Eyegaze programs. The user calls up a desired program by looking at the

Eyegaze key next to his program choice.

Figure: Main Menu

Main Menu Options:

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7.1 The Phrase Program:

The Phrases program, along with the speech synthesizer, provides quick communications

for non-verbal users. Looking at a key causes a preprogrammed message to be spoken. The

Phrases program stores up to 126 messages, which can be composed and easily changed to

suit the user.

Figure: Phrases Screen

7.2 Typewriter Program:

Simple word processing can be done using the Typewriter Program. The user types by

looking at keys on visual keyboards. Four keyboard configurations, simple to complex, are

available. Typed text appears on the screen above the keyboard display. The user may

"speak" or print what he has typed. He may also store typed text in a file to be retrieved at a

later time. The retrieved text may be verbalized, edited or printed.

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Figure: Alpha Keyboard

7.3 The Telephone Program:

The telephone program allows the user to place and receive calls. Frequently used numbers

are stored in a telephone "book". Non-verbal users may access the speech synthesizer to

talk on the phone.

Figure: Telephone Control Screen

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7.4 Run Second PC:

The Run Second PC program permits the Eyegaze Communication System to act as a

peripheral keyboard and Mouse interface to a Windows computer. The user can run any

off-the-shelf software he chooses on the second computer. He can access the Internet, and

send e-mail by looking at keyboard and mouse control screens on the Eyegaze monitor.

The programs being run are displayed on the second computer's monitor. Typed text

appears simultaneously on the Eyegaze and second pc's screens.

Figure: Frequency Keyboard

For children, two new Eyegaze programs have been added to the Eyegaze System.  Both

run with the Second PC option.  Eye Switch is a big, basic on-screen switch to run "cause

& effect" software programs on a Second PC.  Simple Mouse is an easy mouse control

program to provide simplified access to educational software on a Second PC.

22

Figure: Mouse control screen

7.5 The Lights & appliances Program:

The Lights & appliances Program which includes computer-controlled switching

equipment, provides Eyegaze control of lights and appliances anywhere in the home or

office. No special house wiring is necessary. The user turns appliances on and off by

looking at a bank of switches displayed on the screen.

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Figure: Lights and Appliances

7.6 Paddle games & Score Four:

These are the visually controlled Games.

7.7 Read Text Program:

The Read Text Program allows the user to select text for display and to "turn pages" with

his eyes. Any ASCII format text can be loaded for the user to access. Books on floppy disk

are available from Services for the Blind.

7.8 Television:

Television programs can be displayed directly on the desktop Eyegaze System screen.  On-

screen volume and channel controls provide independent operation.  (Not available on the

Portable Eyegaze System.)

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7.9 A web browsing system using Eyegaze input:

Recently, the eye-gaze input system was reported as a novel human-machine

interface. The operation of this system only requires user eye movement. Using

this system, many communication aid systems have been developed for people

with severe physical handicaps, such as ALS patients. We have reported a new

Eyegaze input system already. It utilizes a personnel computer and a home

video camera to detect eye-gaze under natural light. In this paper, we propose a

new web browsing system for our conventional eye-gaze input system.

Eye-Gaze input system has to detect gaze direction of users. Our Eye-Gaze

input system

Runs image analysis software for Eye-Gaze detection.

On horizontal Eye-Gaze detection, the detecting method uses the difference in

reflectance between the Iris and the sclera; this is estimated by the difference in

reflectance between the Iris and the sclera; this is estimated by the difference of

integral value of the brightness on area A and B, shown in fig. On vertical Eye-

Gaze detection, we draw attention to the vertical movement of Iris. The light

intensity distribution from eye image changes with Iris movement. The light

intensity distribution from eye image changes with Iris movement.

In this, we propose the web browsing system using above methods. The

indicators for web browsing are displayed on monitor of personnel computer.

By switching 3 function groups, this system offers many

Function groups, this system offers many functions such as “mouse cursor

control”, ”scrolling of screen” , “decision of selected object” , “refreshing web

page” and “text input by using screen keyboard”. User can switch function

groups by gazing “menu” indicator.

This system analyzes the location of selectable object on web page, such as

hyperlink, radio button, edit box, etc.

25

This system stores the locations of these objects, in other words, the mouse

cursor skips to the object of candidate input. Therefore it enables web browsing

at a faster pace.

The evaluation experiments for the proposed system were conducted with five

objects. Subjects were browsing through two web sites, the results show that

the subjects can operate this system as they planned, and correct easily errors in

operation.

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CHAPTER 8

TECHNOLOGIES AND TECHNIQUES

The most widely used current designs are video-based eye trackers. A camera focuses on one or both eyes and records their movement as the viewer looks at some kind of stimulus. Most modern eye-trackers use contrast to locate the center of the pupil and use infrared and near-infrared non-collimated light to create a corneal reflection (CR). The vector between these two features can be used to compute gaze intersection with a surface after a simple calibration for an individual.

Two general types of eye tracking techniques are used: Bright Pupil and Dark Pupil. Their difference is based on the location of the illumination source with respect to the optics. If the illumination is coaxial with the optical path, then the eye acts as a retro reflector as the light reflects off the retina creating a bright pupil effect similar to red eye. If the illumination source is offset from the optical path, then the pupil appears dark because the retro reflection from the retina is directed away from the camera.

Bright Pupil tracking creates greater iris/pupil contrast allowing for more robust eye tracking with all iris pigmentation and greatly reduces interference caused by eyelashes and other obscuring features. It also allows for tracking in lighting conditions ranging from total darkness to very bright. But bright pupil techniques are not effective for tracking outdoors as extraneous IR sources interfere with monitoring.

Eye tracking setups vary greatly; some are head-mounted, some require the head to be stable (for example, with a chin rest), and some function remotely and automatically track the head during motion. Most use a sampling rate of at least 30 Hz. Although 50/60 Hz is most common, today many video-based eye trackers run at 240, 350 or even 1000/1250 Hz, which is needed in order to capture the detail of the very rapid eye movement during reading, or during studies of neurology.

Eye movement is typically divided into fixations and saccades, when the eye gaze pauses in a certain position, and when it moves to another position, respectively. The resulting series of fixations and saccades is called a scan path. Most information from the eye is made available during a fixation, but

27

not during a saccade. The central one or two degrees of the visual angle (the fovea) provide the bulk of visual information; the input from larger eccentricities (the periphery) is less informative. Hence, the locations of fixations along a scan path show what information loci on the stimulus were processed during an eye tracking session. On average, fixations last for around 200 ms during the reading of linguistic text, and 350 ms during the viewing of a scene. Preparing a saccade towards a new goal takes around 200 ms.

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CHAPTER 9

APPLICATIONS

Every year more than 100,000 people are diagnosed with motor neurone diseases. Typically, even when all other ways of communicating are either severely damaged or completely lost, the eyes still function. Communication by Gaze Interaction (COGAIN) is a Network of Excellence designed specifically to help people with these disabilities to communicate more effectively with eye gaze. At the COGAIN stand you can see how this technology is used by a person who relies on it.

Current eye tracking equipment allows users to generate text on a computer by using eye gaze. Users are able to select letters and numbers by looking at a keyboard on a screen with their eyes, and can construct words and sentences that can be spoken aloud by the system. Using these systems both empowers and enables people with disabilities as they can now communicate without the need for an assistant or helper, giving the users greater freedom in their lives.

Eye tracking systems that allow text entry by eye gaze have been in existence for about two decades, but the technology is still only available to a small portion of the potential user population. Obstacles for more wide-spread use currently include: the high cost of eye tracking equipment, the limitation that gaze communication applications may only work with a particular dedicated eye tracking device, and finally that eye tracking devices are often hard to use and require experts to operate them.

A wide variety of disciplines use eye tracking techniques, including cognitive science, psychology (notably psycholinguistics, the visual world paradigm), human-computer interaction (HCI), marketing research and medical research (neurological diagnosis). Specific applications include the tracking eye movement in language reading, music reading, human activity recognition, the perception of advertising, and the playing of sport. Uses include:

Cognitive Studies Medical Research Laser refractive surgery Human Factors

29

Computer Usability Translation Process Research Vehicle Simulators In-vehicle Research Training Simulators Virtual Reality Adult Research Infant Research Adolescent Research Geriatric Research Primate Research Sports Training fMRI / MEG / EEG Commercial eye tracking (web usability, advertising, marketing,

automotive, etc) Finding good clues Communication systems for disabled Improved image and video communications Computer Science: Activity Recognition

Commercial applications

In recent years, the increased sophistication and accessibility of eye tracking technologies have generated a great deal of interest in the commercial sector. Applications include web usability, advertising, sponsorship, package design and automotive engineering. In general, commercial eye tracking studies function by presenting a target stimulus to a sample of consumers while an eye tracker is used to record the activity of the eye. Examples of target stimuli may include websites, television programs, sporting events, films, commercials, magazines, newspapers, packages, shelf Displays, consumer systems (ATMs, checkout systems, kiosks), and software. The resulting data can be statistically analyzed and graphically rendered to provide evidence of specific visual patterns. By examining fixations, saccades, pupil dilation, blinks and a variety of other behaviors researchers can determine a great deal about the effectiveness of a given medium or product. While some companies complete this type of research internally, there are many private companies that offer eye tracking services and analysis.

The most prominent field of commercial eye tracking research is web usability. While traditional usability techniques are often quite powerful in

30

providing information on clicking and scrolling patterns, eye tracking offers the ability to analyze user interaction between the clicks. This provides valuable insight into which features are the most eye-catching, which features cause confusion and which ones are ignored altogether. Specifically, eye tracking can be used to assess search efficiency, branding, online advertisements, navigation usability, overall design and many other site components. Analyses may target a prototype or competitor site in addition to the main client site.

Eye tracking is commonly used in a variety of different advertising media. Commercials, print ads, online ads and sponsored programs are all conducive to analysis with current eye tracking technology. Analyses focus on visibility of a target product or logo in the context of a magazine, newspaper, website, or televised event. This allows researchers to assess in great detail how often a sample of consumers fixates on the target logo, product or ad in this way, an advertiser can quantify the success of a given campaign in terms of actual visual attention.

Eye tracking provides package designers with the opportunity to examine the visual behavior of a consumer while interacting with a target package. This may be used to analyze distinctiveness, attractiveness and the tendency of the package to be chosen for purchase. Eye tracking is often utilized while the target product is in the prototype stage. Prototypes are tested against each other and competitors to examine which specific elements are associated with high visibility and appeal.

One of the most promising applications of eye tracking research is in the field of automotive design. Research is currently underway to integrate eye tracking cameras into automobiles. The goal of this endeavor is to provide the vehicle with the capacity to assess in real-time the visual behavior of the driver. The National Highway Traffic Safety Administration (NHTSA) estimates that drowsiness is the primary causal factor in 100,000 police-reported accidents per year. Another NHTSA study suggests that 80% of collisions occur within three seconds of a distraction. By equipping automobiles with the ability to monitor drowsiness, inattention, and cognitive engagement driving safety could be dramatically enhanced. Lexus claims to have equipped its LS 460 with the first driver monitor system in 2006, providing a warning if the driver takes his or her eye off the road.

31

Since 2005, eye tracking is used in communication systems for disabled persons: allowing the user to speak, send e-mail, browse the Internet and perform other such activities, using only their eyes. Eye control works even when the user has involuntary movement as a result of Cerebral palsy or other disabilities, and for those who have glasses or other physical interference which would limit the effectiveness of older eye control systems.

Eye tracking has also seen minute use in autofocus still camera equipment, where users can focus on a subject simply by looking at it through the viewfinder.

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CHAPTER 10

FOR PEOPLE WITH LIMITED EYE CONTROL

Scanning Keyboard is the new row/column keyboard with an on-screen eye

"switch" for people with limited eye movement.  The switch can be placed on

either side, above, or below the keyboard to accommodate users with only

horizontal movement, or only vertical movement.  The user may "speak" what

he has typed.

10.1. Environment required for an Eyegaze system

Because eyetracking is done using infrared light.Eyegaze system must take

care of light sources in the room in order to ensure the best accuracy. The

Eyegaze System must be operated in an environment where there is limited of

ambient infrared light. Common sources of infrared light are sunlight and

incandescent light bulbs. The System makes its predictions based on the

assumption that the only source of infrared light shining on the user's eye is

coming from the center of the camera. Therefore, stray sources of infrared

may degrade the accuracy or prevent Eyegaze operation altogether. The

System works best away from windows, and in a room lit with fluorescent or

mercury-vapor lights, which are low in infrared.

10.2. New portable Eyegaze System

The Portable Eyegaze System can be mounted on a wheelchair and run from a

12-volt battery or wall outlet.  It weighs only 6 lbs (2.7 kg) and its dimensions

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are 2.5"x8"x9" (6.5cm x20cm x23cm).  The Portable Eyegaze System comes

with a flat screen monitor and a table mounted for its monitor.  The monitor

can be lifted off the table mount and slipped into a wheelchair mount. 

Figure: Portable Eyegaze System Mounted on Wheelchair

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Figure: Screen of Eyegaze System

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10.3 THE EYEGAZE COMMUNICATION SYSTEM:

COMPONENTS & PRICES

Desktop Eyegaze System $14,900 US$

Software Programs

Main Menu

Keyboard

Games

Read Text

Teach

Settings Program

 

Hardware

Desktop computer with Windows 2000, Video frame grabber,

sound,

CD and floppy drives

15" LCD Flat Panel Monitor

Adjustable monitor tray with camera bracket

High-speed infrared sensitive camera and lens

Surge protector, cables and connectors

 

Upgrades and Options

Portable computer (in place of desktop computer)

Computer access (hardware and software to run a PC)

Lights & Appliances

Telephone

Television

 

$1000

$500

$350

$350

$350

Options for use outside the U.S. are slightly different.

All money is in U.S. Dollars.

The above prices do not include shipping costs or travel-related installation expenses.

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The prices and specifications are subject to change without notice.

Virginia residents add 4.5% sales tax.

At each camera image sample, the Edge Analysis System generates:

an eye-found flag indicating whether or not the eye is visible to the camera and thus whether or not a valid gazepoint is calculated,

x-y coordinates of the subject's gazepoint on the computer screen, pupil diameter, 3-dimensional location of the eyeball center within the camera field-of-

view, an indicator of head location and movement, and fixation and saccade analysis.

The Edge Analysis System is robust and extremely easy to calibrate. RMS tracking errors are typically 0.25 inch (0.63 cm) or less and the advanced image processing algorithms in the System explicitly accommodate several common sources of gazepoint tracking error:

Head Range Variation Pupil Diameter Variation Corneal Reflection Straddling Pupil Edge

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Figure: Eyegaze System Communication System

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CHAPTER 11

CONCLUSION

Today, the human eye-gaze can be recorded by relatively unremarkable

techniques. This thesis argues that it is possible to use the eye-gaze of a

computer user in the interface to aid the control of the application. Care must

be taken, though, that eye-gaze tracking data is used in a sensible way, since

the nature of human eye-movements is a combination of several voluntary and

involuntary cognitive processes.

The main reason for eye-gaze based user interfaces being attractive is that the

direction of the eye-gaze can express the interests of the user-it is a potential

porthole into the current cognitive processes-and communication through the

direction of the eyes is faster than any other mode of human communication.

It is argued that eye-gaze tracking data is best used in multimodal interfaces

where the user interacts with the data instead of the interface, in so-called non-

command user interfaces.

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CHAPTER 12

REFERENCES

http://www.eyegaze.com/content/assistive-technology http://www.eyegaze.com/content/eyetracking-research-tools http://www.gschlosser.de/eyegaze_english.htm http://www.sensorysoftware.com/132.html http://www.diku.dk/hjemmesider/ansatte/panic/eyegaze/node19.html http://www.eyetechds.com/

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