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of the eye mouse are extremely pertinent.The future development of the eye mouse will
not only empower the handicapped, but will also become a powerful tool for advertising
and GUI development. Researchers have used the device to associate pupil dilation with
action and emotion.
D. Technologies combining several senses
Brain-actuated control
This technology combines eye-movement, facial muscle, and brain wave bio-potentials
detected at the user's forehead to generate computer input useful for a variety of tasks
and recreations.
The forehead is a convenient, non-invasive measuring site, rich in a variety of bio-
potentials. Signals detected by sensors in a headband are sent to an interface box contain-
ing a bio-amplifier and signal processor.The interface box connects to the computer's
serial port.The forehead signals are amplified, digitised and translated by a decoding
algorithm into multiple command signals, creating an efficient, intuitive and easily
learned hands-free control interface.
Three different types (or channels) of control signals are derived from the forehead
signals.The lowest frequency channel is called the ElectroOculoGraphic or EOG signal.
This is a frequency region of the forehead bio-potential that is responsive primarily to
eye movements.The EOG signal is typically used to detect left and right eye motion.
This signal can be mapped to left and right cursor motion or on/off switch control.
The second type of control signal is called the ElectroEncephaloGraphic or EEG signal.
This region is subdivided into frequency bands called in some cases `Brainfingers'.These
frequencies reflect internal brainwave activity as well as subtle facial muscle activity. A
wide range of facial muscles can affect these frequency bands, and users typically learn
control of their Brainfingers first through subtle tensing and relaxing of various muscles
including forehead, eye and jaw muscles. After a little experience with the Cyberlink sys-
tem, most users begin to experiment with more efficient, internal brain-based control
methods. Since this frequency region is sensitive to both mental and muscular signals it is
called the `BrainBody' signal. Brainfinger control is continuous or analogue and is typically
used for tasks such as control of vertical or horizontal cursor movement. For example, one
Brainfinger may be used to control vertical movement while a second Brainfinger (or
some other signal channel) is used to control horizontal movement.
The third channel is called the ElectroMyoGraphic or EMG signal.This signal prima-
rily reflects facial muscle activity. It is typically used for discrete on/off control of pro-
gram commands, switch closures, keyboard commands, and the functions of the left and
right mouse buttons. Specific facial and eye movement gestures can be discriminated by
software means, and mapped to separate mouse, keyboard, and program functions. For
individuals with limited control of their facial muscles, the software can be formatted to
use BrainBody or EOG inputs (instead of EMG) to activate switch closures and mouse
button clicks.
These brain-actuated control systems provide an intuitive, direct, easily learned, hands-
free, and language-independent control interface.They represent a cutting-edge techno-
logical achievement in the user-computer interface, making possible new computer con-
trol methods to empower the disabled and all users of future technology.
Human Interfaces