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screen cursor position.The selection, emulating the pressing of a mouse button, is
achieved by the software detecting when the eye is held still for half a second or the
user winks.This differs from natural eye blink and the eye tracker will not treat
blinking as a valid signal.The use of a binocular system allows the closure of the
right and left eyes to emulate pushing the right and left mouse buttons respectively.
- Electrode interface:The eyes act like a dipole in space and create an electrochemical
field in the surrounding extra cellular fluid.With an upward look, the upper parts of
the eyes become more positively charged than the lower parts.The inverse is true if
the person looks down. If the person looks right, the region to the right of the eyes
becomes more positive, and vice versa if the person looks left.These differences
around the eyes can be transduced by scalp electrodes, and detected by an instrumen-
tation amplifier.
Where is the eye mouse used?
Besides helping people with disabilities control computers, there are appealing eye
mouse uses for people without disabilities.The novel use of the eye in conjunction with
the eye mouse optimises the interaction between man and machine. It enables the user
to utilise both the keyboard and the mouse simultaneously, allowing greater efficiency
and enhancing the human interactions with the computer. In addition, the eye mouse
can be used in the development and design of graphical user interfaces or in the analysis
of human eye-response to still and motion images, such as printed advertisements and
television commercials.The eye mouse can be usefully employed in advertising, using
critical eye-gaze information to investigate which advertisements attract more intended
customers and on what information viewers are making their buy or no-buy decisions.
Clients may find that the current format of an advertisement places a critical piece of
information in a place that is overlooked, sacrificing potential sales. It enables the agen-
cies to create better, more effective advertisements for their audience.
The eye mouse enables software developers to make better use of interfaces and create
easier-to-use applications. It allows them to discover how the user interacts visually with
their product. Application analysis is good for determining what makes a successful graph-
ical user interface. Knowing where a person looks during various use phases of an applica-
tion allows developers to design better GUI's to accommodate differing work modes. A
possibility for future GUI designs is an intelligent interface that detects the type of work
mode the user is in and automatically changes its layout to suit that type of work.
In addition, it provides a revolutionary technology to the PC gaming industry. For the
first time, games are able to utilise two interfaces simultaneously in both the hands and in
the eyes. It can be applied to virtual reality and could act as a tool for tracking the posi-
tion of an object such as a head or a hand.
Current scope and future development of the technology
There are currently a significant number of eye mouse products on the market. Every
system and product has the ultimate goal of replacing the traditional hand-controlled
mouse.The `mouse' is based around some intuitive standards and any device which could
replace it must follow these same principles.
For thousands of people, an extreme disability such as severe palsy or sclerosis deprives
them of the use of their limbs and facial muscles. Approximately 30,000 people are cur-
rently afflicted with amyotrophic lateral sclerosis, with a further 5,000 cases reported
annually in the U.S. For those who are unable to control a standard mouse, the benefits
Human Interfaces