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AIDS
FOR VISUAL IMPAIRMENT.
PAGE
INDEX
AIDS FOR BLIND PEOPLE.
In
the case of blind people for whom their missing 'sense' has
to be substituted with the remaining senses, many aids have
been made that enable access to computer through the use of
hearing, for example, or touch. This enables a blind person
to read utilising residual ability. What matters most, in
fact, is achieving the objective, not how it is achieved.
This is often the case not only for blind people but for people
with all kind of disabilities.
The Braille
Bar (also called Braille Terminal or display Braille) is,
together with the vocal sythethizer, the principal information
technology tool for blind people. Applied to any computer,
it enables the content of the screen to be 'translated' in
a Braille text. It is important to consider the number of
cells in a bar, there can be 80, 40, 20 cells. Those bars
containing 80 cells can contain an entire row of the computer
screen, however they are very expensive and generally people
that use them have highly professional jobs. In a Windows
environment the length of the bar is changeable and therefore
it is not important to have a bar of 80 cells, or even higher.
The most common bars have 40 cells, similar to the lenght
of Braille text on paper. Bars with less than 40 cells are
decidedly more economical and generally they're part of an
wider system: small mobile instruments with various functions,
similar to the ones of palm pilots.
This aid has
also a long history. The first vocal sythesizers took the
form of an external apparatus connected to PCs through a parallel
or serial 'port' with part of the software enabling the reading
of text on the screen (or part of it) utilising phonetic rules
of a predetermined language. Today Vocal sythesizers are software
that use the Audio Card of the Computer. They manage, like
their precedessors, the reading of text in different languages.
A text can
be read in different ways: the reading of a single key, word
by word, line by line, continuous reading, with special characters
and with attributes of text like 'spelling', underlining,
italic, and so on.
A
Braille bar or a voice synthesizer cannot work without the
aid of a programme indicating the machine how to function.
It becomes indispensible to establish what part of the screen
needs to be read automatically by the Braille bar or by the
sythesizer. This software is a screen reader. The evolution
of screen readers has been very fast in the past years. Within
DOS, nothing is unexplored by a blind person, within Windows
almost all applications are accessible thanks to highly adaptable
screen readers able to respond to the high demands of today's
graphics.
Functions
of the screen reader can be obviously adapted thanks to specially
programmed keys on the keyboard or on the Braille bar that
can highlight particular parts to be read, such as lines,
characters, words or the content of a window.
Braille printers
enable printing onto paper of any text from a word processor
in the raised characters of Braille format.
Various models
differentiate by printing times and (the more sophisticated
ones) by the ability to print on both sides of the paper withouth
them interfering with each other. This can reduce the weight
and the size of a Braille printer by up to 50%. Even though
functioning of the printer is not dissimilar from a regular
printer, difficulties arise by the necessity to trascribe
text in correct 6-point Braille format. It requires that upper
case letters or numbers are preceded by a special symbol.
Braille printing is also managed by software able to adapt
the text to the needs of different Braille writings.
A scanner is
a tool that captures a graphic image and transforms it into
digital information. OCR programmes (Optical Character Recognition)
recognise characters on paper and transform the image in a
wordprocessor document that can be saved onto disk, printed
or read in Braille or the vocal sythesizer. Scanners and OCRs
are products for general use, however there are some OCR programmes
specifically made for blind people: they can decode text even
if it's not correctly positioned on the scanner, they can
recognise the page structure even if divided in columns, titles
and paragraphs, as well as eliminate drawings, photographs
and diagrams. There are also OCR-connected scanners that can
procede onto an immediate reading of the text. It has to be
noted however that, againg, scanners and OCR, have not been
created for people with disabilities, they simply have change
the way businesses and offices work enabling better management
of documents and text.
AIDS FOR PARTIALLY SIGHTED PEOPLE
For partially
sighted people the flexibility of information technology enables
various dynamic ways to enlarge text and change colours and
backgrounds on the screen.
They are tools
that through a close-circuit television system can film the
image of a text and magnify it before projecting it onto a
screen. With an electronic zoom it is possible to make enlargements.
This can reduce the visual field, therefore the user must
move the text around in order to read it under the view-finder.
This can be achieved easily with a manual 'slide'. Video-magnifiers
are essentially used for reading paper-printed text. Obviously
there are software programmes that enable magnification in
personal computers completely independently.
It consists
of a software programme enlarging the characters appearing
on the screen so that partially sighted people can use a personal
computer. They can be loaded into the hard disk of any computer.
The magnification obviously reduces the visual field, therefore
through a serch system (usually operated with the mouse) it
is possible to select the part of the screen that one wishes
to see. These programmes enlarge caracters, images or icons,
and colour contrasts, the shape of the mouse pointer as well
as formatted documents.
Many magnifiers
are also provided with a voice sythesizer, which can be very
useful when one needs to read long lines of text that do not
need to be spell checked. Although this system is not very
sophisticated, many partially sighted people like to use this
combination of magnification and voice sythesis to manage
applications.
These magnifiers
work in the DOS system as well as in Windows and are easily
adapted to professional requirements, for study or for recreational
use.
The problem
of magnification of characters can sometimes find an adequate
solution through normal software programmes in graphic Windows
TM, which enables the use of a set of characters of various
dimensions, shapes and formats - as well as using Disability
Options of Windows. However, often icons and images cannot
be managed very well, therefore the use of a magnifier would
be preferred. The solutions always depends on the type of
residual vision of the user and what they wish to operate
the computer for.
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