the eyegaze communication system

ABSTRACT

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.
1. INTRODUCTION

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.Who's using the Eyegaze System?

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.
2.1The skills needed by the user :

2.1.1 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):
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.

2.1.2 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 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 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.

2.2 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.
1. 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 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.

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

2.3.1 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.

2.3.2 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.

2.3.3 Memory:

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.


3. How does the Eyegaze System work?

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.
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.
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.
4 .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.

5.Uses of Eyegaze

5.1 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)
• TEACH new users with simplified screens. (Teach Screens)

5.2 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)

6. 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.


Main Menu options :

6.1 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.

6.2 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.

6.3 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.

6.4 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.

Fig.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.

6.6 Paddle games & Score Four:
These are the Visually controlled Games.
6.7 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.
6.8 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.)

7. 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.

8.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.

9. 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 are 2.5"x8"x9" (6.5cm x20cm x23cm). The Portable Eyegaze System comes with a flat screen monitor and a table mount for its monitor. The monitor can be lifted off the table mount and slipped into a wheelchair mount.


10. 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 are in U.S. Dollars.
• The above prices do not include shipping costs or travel-related installation expenses.
• The prices and specifications are subject to change without notice.
• Virginia residents add 4.5% sales tax.

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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.


Bibliography
[1] IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATIO ENGINEERING,VOL.10,NO.1,MARCH 2002
The Camera Mouse:Visual Tracking of Body features to Provide ComputerAccess 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
Pages 159-174