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1
GETTING STARTED
The Eyegaze Edge is a tablet-based communication and control system than enables people to
connect with the world using only their eyes. To operate the system, the Eyegaze Edge control screen
is positioned in front of the user so he can comfortably access the screen with his eyes. Screen
displays typically include a variety of control and communication functions that the Eyegaze Edge is
capable of executing. When the user focuses his gaze on a desired "key" for a fraction of a second, the
Eyegaze Edge executes the associated function, such as verbalizing a phrase, typing a keyboard
character, or sending an email.
1.1
Principle of Operation
A specialized camera mounted below the Eyegaze control screen is focused on one of the user's eyes.
The camera's image of the eye is displayed in the upper right or left corner of the screen. The eye
image assists in optimally positioning the camera. Once positioned, the camera takes 60 pictures per
second of the eye; those images are analyzed in real time to determine the user's gaze point on the
screen.
Eye tracking is done utilizing a small infrared light (LED) mounted in the center of the camera lens. The
LED illuminates the eye and provides a bright image of the pupil and bright spot reflecting off the
cornea. The bright corneal reflection is often referred to as the glint spot. Sophisticated image-
processing software in the system continually tracks the center of the pupil and the center of the glint
spot. Based on the relative positions of the pupil center and the glint spot, the Eyegaze Edge predicts
where on the control screen the user is looking.
Typically the Eyegaze Edge predicts the user's gaze point with an accuracy of better than 1/4-inch,
enabling the user to activate keys as small as a 5/8-inch square. As feedback to the user, the Edge
displays a red dot, called the locator dot, on the screen at either the point where the user is looking or in
the center of the key the user is looking at, based on user preference.
The user operates the Eyegaze Edge by looking at rectangular keys that are displayed on the control
screen. To "press" a key visually, the user looks at the key for a specified period of time, called the
gaze duration, usually 1/4-second to 2/3-second. When the key is activated it flashes. The system then
takes the action associated with that key.
1.2
Requirements for Use
To operate the Eyegaze Edge effectively, a person should have good control of at least one eye. He
should be able to move his gaze freely over the full range of the control screen. He should be able to fix
his gaze at any desired position on the screen for a period of about 1/2-second in order to select and
activate the various keys.
Image: Eye with bright pupil and glint spot
2
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