Eye gaze

Eye gaze Communication

Abstract

The field of human computer interaction has been undergoing a new renaissance

lately. While many companies have, and continue to spend millions to develop

highly visually appealing GUIs and state-of-art interaction systems for the

common users since the inception of desktops, the development of interactive

systems for the disabled has taken a kick start relatively recently. And the

Eyegaze systems are one of the most pivotal inventions in this context. 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. Eye gaze

Systems are being used to write books, attend school and enhance the quality of

life of people with disabilities all over the world.

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TABLE OF CONTENTS

1 INTRODUCTION

1.1 System overview

1.2 System features

1.3 System output

1.4 System software

1.5Eyegaze analysis system

2 SKILLS NEEDED BY EYEGAZE USERS

2.1 Good control of one eye

2.2 Adequate vision

2.3 Ability to maintain a position in front of eyegaze monitors

3 WORKING OF EYEGAZE SYSTEMS

4 MENUS OF EYEGAZE SYSTEMS

4.1 Main menu

4.2 The phrase program

4.3 Typewriter program

4.4 Telephone program

4.5 Run second pc

4.6 The lights and appliances

4.7 Paddle games and score four

4.8 Read text program

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4.9 Television

4.10A web browsing system using eyegaze input

5 HOW TO RUN THE EYEGAZE SYSTEMS?

6 USES OF EYEGAZESYSTEMS

6.1 The basic eyegaze can

6.2 With options eyegaze can

7 ENVIRONMENT REQUIREDFOR EYEGAZE SYSTEM

8 EYE TRACKING V/S GAZE TRACKING

9 DEVELOPMENTS IN EYEGAZE TECHNOLOGY

10 EYETRACKING APPLICATIONS

11 BENEFITS OF EYEGAZE

FACTS OF EYEGAZESYSTEM

12 DISADVANTAGES OF EYEGAZESYSTEM

13 CONCLUSION

14 REFERENCES

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CHAPTER 1

INTRODUCTION

1.1 System Overview

Most of us blessed to operate the computer with ease using our hands. But there

are some who can’t use their hands and for them the voice guided systems have

been in use for quite some time now. But about paralytic patients with no

mobility and speech? Even when their brains are functional and they are visually

and aurally blessed to know what is going around. So shouldn’t they be able to

effectively use their intelligence? Now they can with the Eyegaze communication

system.

Fig 1.1 Eyegaze system in computer

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

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

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

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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.

1.2 SYSTEM FEATURES

Calibration: Fully automated calibration is fast (15 - seconds), easy and long

lasting.

Accuracy: Highly accurate and tolerant to many variations, such as pupil drift

and head range variation - typical average bias error 0.45 degrees. Good tolerance

to ambient infrared light and to high-speed head motion.

Remote Video Tracking: Unobtrusive and non-distracting with nothing attached

to the subject.

Accommodates Most Human Eye Variations: Useable by 90% of the people

who try it, functional with most glasses and contacts.

Binocular Eye Tracking: Tracks both of the subject’s eyes to increase gaze

point accuracy by adjusting for head rotation.

Trace Suite: This suite of programs captures a subject’s gaze when presented

with static or moving images or during computer operations. In addition to

generating the standard data of our Analysis System, the user’s gaze and the

stimulus are linked so they can be replayed and studied in depth. The observer

can view the subject’s screen, eye images and gaze point in real time on a

separate monitor.

Eyegaze Software Development Tool Kit: EgWin API - Eyegaze Function

Library, Gaze Tracking Demonstration Program (C source code), EgTraceImage

and EgTraceText Programs (C source code), Fixation/Saccade Analysis Function

(C source code), EgServer and EgClientDemo Programs (C source code)

NYAN Analysis Tool: NYAN is an analysis tool based on screen recording

technology with synchronized gaze and mouse data. It can be used instead of the

Trace Suite to analyze web pages and intranet applications as well as standard

application software and still images. In addition to Gaze Video Overlay

Playback, Scanpath Analysis and Area of Interest Analysis it provides a way to

visualize subjective perception of individuals or groups of people by means of

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Attentional Landscapes technology. NYAN also provides group statistics and

many export possibilities

1.3 SYSTEM OUTPUTS

At each camera image sample, the Eyegaze 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 centre within the camera field of view, an

indicator of head location and movement, and

Fixation and saccade analysis.

1.4 SYSTEM SOFTWARE

Eyegaze Software: (Eyegaze.dll), video camera interface, eye image processing,

gaze point calculation Trace Program (trace.exe), Calibration Program

(calibrate.exe), Eyegaze Demonstration Program (gazedemo.exe)

Windows XP Professional

THE EYEGAZE COMMUNICATION SYSTEM

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1.5 EYEGAZE ANALYSIS SYSTEMS

Eyegaze Analysis System

Mini computer

Runs all existing Eyegaze Analysis System programs

Expandable: will allow you to add on binocular eye tracking and wide field of

view camera lenses in the future

Fig 1.2 Eyegaze analysis system Fig1.3 Binocular system

Binocular Eyegaze Analysis System

Improved accuracy!

Provides two independent measurements of gaze point

Averaging of gaze points from both eyes gives you an improved estimate of gaze

point

A 30% reduction in point-to-point error

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CHAPTER 2

SKILLS NEEDED BY EYEGAZE USERS

2.1Good control of 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.

2.2Adequate vision

The user should be able to view the screen correctly.

2.3 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.

2.4 Mental Abilities

Ability to read

Memory

Cognition

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CHAPTER 3

WORKING OF EYEGAZESYSTEMS

3.1 OVERVIEW

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.

Fig 3.1 Parts showing eyegaze system

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

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System predicts the gazepoint with an average accuracy of a quarter inch or

better.

Fig 3.2 Working of Eyegaze system

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. 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.

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CHAPTER 4

Menu of Eye-gaze Systems

4.1The 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.

Fig 4.1 Main menu screen

4.2 The Phrase Program

The Phrases program, along with the speech synthesizer, provides

quick communications for non-verbal users. Looking at a key causes a pre-

programmed message to be spoken. The Phrases program stores up to 126

messages, which can be composed and easily changed to suit the user.

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Fig 4.2 Phrases screen

4.3 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.

Fig 4.3 Alpha Keyboard

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4.4The 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

Fig 4.4 Telephone control system

4.5Run 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

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.

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Fig 4.5 Mouse control screen

4.6 Paddle games & Score Four

These are the Visually controlled Games.

4.7 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.

4.8 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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4.9 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

4.10 A web browsing system using eye-gaze 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 an 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

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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. The

vertical Eye-Gaze can be detected using this change.

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

Hardware configuration and screen shots. 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, shown in fig.4.

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

hyperlink, radio button, edit box, ETC.

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 5

HOW TO RUN 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

5.1 Eyegaze Analysis EyeFollower 2.0

Accommodates all natural head motions during normal computer operation

Automatic Eye Acquisition – The EyeFollower 2.0 automatically acquires the

eyes when the user enters the workspace and it rapidly re-acquires the eyes when

he returns his attention to the screen after turning his head away

Head Motion Volume

o Side to Side: 20 inches (51cm)

o Up and down: 12 inches (30cm)

o Back and forth: 15 inches (38cm)

Head Speed: 8 inches/sec (20cm/sec)

Head Accelerations: 20 inches/sec (50cm/sec)

Fig 5.1 Eyegaze system range

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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

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)

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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)

CHAPTER 7

Environment required for an Eyegaze system

Because eye tracking 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.

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CHAPTER 8

EYETRACKING V/S GAZE TRACKING

Eye trackers necessarily measure the rotation of the eye with respect to the

measuring system. If the measuring system is head mounted, as with EOG, then

eye-in-head angles are measured. If the measuring system is table mounted, as

with scleral search coils or table mounted camera (“remote”) systems, then gaze

angles are measured.

In many applications, the head position is fixed using a bite bar, a forehead

support or something similar, so that eye position and gaze are the same. In other

cases, the head is free to move, and head movement is measured with systems

such as magnetic or video based head trackers.

For head-mounted trackers, head position and direction are added to eye-in-head

direction to determine gaze direction. For table-mounted systems, such as search

coils, head direction is subtracted from gaze direction to determine eye-in-head

position.

Eye tracking in practice

A great deal of research has gone into studies of the mechanisms and dynamics of

eye rotation, but the goal of eye tracking is most often to estimate gaze direction.

Users may be interested in what features of an image draw the eye, for example.

It is important to realize that the eye tracker does not provide absolute gaze

direction, but rather can only measure changes in gaze direction. In order to know

precisely what a subject is looking at, some calibration procedure is required in

which the subject looks at a point or series of points, while the eye tracker records

the value that corresponds to each gaze position. (Even those techniques that

track features of the retina cannot provide exact gaze direction because there is no

specific anatomical feature that marks the exact point where the visual axis meets

the retina, if indeed there is such a single, stable point.) An accurate and reliable

calibration is essential for obtaining valid and repeatable eye movement data, and

this can be a significant challenge for non-verbal subjects or those who have

unstable gaze.

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CHAPTER 9

Developments in Eyegaze Technology

LC technologies have recently developed a 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 are

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

flat screen monitor and a table mounts for its monitor. The monitor can be lifted

off the table mount and slipped into a wheelchair mount.

Fig 9.1The Scientist Stephan Hawking uses this system with wheelchair to

communicate.

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CHAPTER 10

EYETRACKING APPLICATIONS

Eye tracking has significant potential for the creation of new and exciting applications in a

broad range of fields:

Neurosciences /Neuropsychology

Vision Research

Experimental Psychology

Cognitive Psychology

Psycholinguistics

Psychiatry /Mental Health

Human Factors /Ergonomics /Industrial Design /Human Computer Interaction

and Usability Research/ Informatics studies...

Developmental Psychology

Science of Education

Reading diagnostics and remediation

Medicine /Opthalmology

Communication Research - Media Studies /Media Psychology

Transportation: Flight simulators /driving simulators

Robotics - remote vision control

Video and arcade games

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CHAPTER 11

ADVANTAGES

People who have used the alphabet clustering system realize that this old process

can become tiresome and confusing (picture of alphabet clustering is shown

below). However, this newer method of a spreadsheet-like communication board

is useful because it can cater to whatever each particular individual would like to

express. There is unlimited vocabulary that can be used on these boards. In

addition, this encoded system can be used with phrases, letters, words, numbers,

pictures or anything else that is needed. Once a person knows how to indicate

what they want in each row and column, the possibilities are infinite amounts of

communication. A user may become frustrated with too much information on a

particular board. However, he or she can simply start a new board with new

vocabulary (but the same colors, letters, and/or numbers). Although users will

need initial training and practice, the benefits of communicating effectively prove

that this short adaptation process is worth it.

Facts

*Other technologies that use the eyes are becoming popular including eye typing.

*LC Technologies, Inc. is developing a system called EYETRACKING, that will

pioneer the use of computers by nonverbal, disabled persons.

*The success of an eye-gaze board will be increased if it is introduced during an

activity that is enjoyable to the individual.

*The eye-gaze board should look age appropriate so that the person is

comfortable using it.

*The ability to express oneself is something that no one should be deprived of.

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CHAPTER 12

DISADVANTAGES

13.1 Disadvantages

It causes diariah

It is not safe even for eyes

It reduces the power sight of the eye

Each method of eye tracking has advantages and disadvantages, and the choice

of an eye tracking system depends on considerations of cost and application.

There are offline methods and online procedures like AttentionTracking. There

is a trade-off between cost and sensitivity, with the most sensitive systems costing

many tens of thousands of dollars and requiring considerable expertise to operate

properly. Advances in computer and video technology have led to the

development of relatively low cost systems that are useful for many applications

and fairly easy to use. Interpretation of the results still requires some level of

expertise, however, because a misaligned or poorly calibrated system can produce

wildly erroneous data.

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http://en.wikipedia.org/wiki/AttentionTracking


CHAPTER 13

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 14

REFERENCES

[1] IEEE TRANSACTIONS ON NEURAL SYSTEMS AND

REHABILITATION ENGINEERING,VOL.10,NO.1,MARCH 2002The Camera

Mouse: Visual Tracking of Body features to Provide Computer Access for People

With Severe Disabilities.

Margrit Betke,James Gips,Peter Fleming

[2] Perceptual Gaze Extent & Level of Detail in VR:Looking outside the Box

Hunter Murphy*,Andrew T. Duchowski*

Department of Computer Science,Clemson University

{hmurphy/Andrew}@vr.clemson.edu

[3] Disability studies Quarterly

Spring 2002,Volume 22,N0.2

www.cds.hawaii.edu

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http://www.cds.hawaii.edu/

Eye gaze

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