B. Auditory technologies
Speech-actuated control: Speech Input Systems
Speech input (or speech recognition) systems allow spoken utterances to serve as input
to a computer.When the system `hears' a sound it recognises, it sends a pre-defined char-
acter or group of characters to the computer which accepts the input just as if it had
been typed on the keyboard.
Speech input systems can be useful for people who have physical disabilities prevent-
ing them from using the keyboard.Their use may reduce cases of repetitive strain injury
and ganglia occurring as a result of long-term, intensive keyboard and/or mouse use. For
those with severe disabilities or those performing complex tasks in constrained environ-
ments mouthsticks, switches and optical headpointers may offer alternative input
Although speech recognition software has been in development for several decades,
effective, commercially available products have only appeared in the last few years. Speech
recognition is a function available in simplified Chinese, English and Japanese language
versions of Microsoft Office XP, and speech recognition techniques can be used to dictate
text into any Office program. Users can improve their productivity by using voice com-
mands to select menu, toolbar, and dialog box options.
Speech recognition is not yet designed for completely hands-free operation. In 2003
the best results can be achieved if a combination of voice and mouse/keyboard is used.
The main drawback to the use of speech recognition to drive public access terminals is
that for anything but the smallest range of commands voice recognition modules must be
`trained' to recognise the particular voice of individual users.
C. Motion tracking technologies
The Eye Mouse
What is an eye mouse?
Computers are generally controlled by hand, using a keyboard, a mouse or a trackball.
Many people who are unable to use their hands can feel disenfranchised by their inability
to utilise this type of equipment.The eye mouse can offer severely disabled people a way
to control a computer simply by moving their eyes or head, controlling the cursor on the
screen and using computers as able-bodied users do.
How does an eye mouse work?
The eye mouse is an ocular prosthetic that allows the cursor to be positioned by
looking and hands-free pointing.Two methods have been developed for the eye mouse:
- Video-based:The binocular eye-tracker has been configured and calibrated to send x
and y co-ordinates of the eye position to the PC, locating the point on the screen at
which the person is looking. Software on the PC takes this information and sends it
to the operating system as a mouse signal, and the x, y co-ordinates determine the
It goes without saying that speech input systems can hold great advantages for all categories of users,
from the able-bodied to the seriously disabled.