Basic Information
relating to Braille
All over
the world, persons with visual handicaps have used Braille as the primary
means to reading information. Also, the concept of Braille has been accepted
as a universal approach that works across the boundaries of the world.
Different countries of the world have adapted the system of Braille to
suit their languages. Irrespective of these changes or modifications,
Visually Handicapped persons understand standard Braille for the Roman
alphabet (English Braille) making it possible to exchange information in
a consistent fashion across different countries.
In these pages, we give an interpretation for Braille as another script
that we can use to represent the letters or aksharas of the languages of
India where the script is presented in a form which may be recognized by
touch or feel. The discussion is in line with the Multilingual Systems
project where software solutions for helping the Visually Handicapped have
been developed at this Institute.
Brief
introduction to Braille
Standard Braille
is an approach to creating documents which could be read through touch.
This is accomplished through the concept of a Braille cell consisting of
raised
dots on thick sheet of paper. The protrusion of the dot is achieved
through a process of embossing. A cell consists of six dots arranged in
the form of a rectangular grid of two dots horizontally and three dots
vertically. With six dots arranged this way, one can obtain sixty three
different patterns of dots. A visually Handicapped person is taught Braille
by training him or her in discerning the cells by touch, accomplished through
his or her fingertips. The image below shows how this is done.
Each arrangement
of dots is known as a cell and will consists of at least one raised dot
and a maximum of six. The image shown later in this page gives examples
of embossed Braille cells. On a Braille sheet, the dots are created by
embossing using a special printer or even a manual machine that simultaneously
embosses the dots. Today, we also have Braille printers which may be connected
to computers on standard printed interfaces. These are generally known
as Braille Embossers.
In the developed world,
Visually Handicapped persons are taught to read Braille at a very early
age. They develop reading skills well enough to read the text books
and reference material and attend schools, often with normal children,
to get integrated into the mainstream of life.
At this point one
might ask "does Braille have the functionality of the printed medium?".
The answer is surprisingly yes, and in schools for the Visually Handicapped,
the libraries will be full of Braille text and reference books. It is true
that Braille books are bulky and cannot be carried around just as easily
as printed books but the point to keep in mind is that we have to
provide a suitable medium for the Visually Handicapped that will enable
them to get educated in the first place. So providing them a resource,
which could be bulky but which will allow them to read is important.
The
Braille Cell
A printed sheet of
Braille normally contains upwards of twenty five rows of text with forty
cells in each row. The physical dimensions of a standard Braille sheet
are approximately 11 inches by 11 inches. The dimensions of the Braille
cell are also standardized but these may vary slightly depending on the
country. The dimensions of a Braille cell, as printed on an embosser is
shown below.
A sheet of Braille may thus
appear to hold information amounting to about a thousand characters (letters
of the alphabet). Later we will see that the designers of the Braille
system had foreseen the need to present information in compact form so
that a set of cells could convey much more information in the string of
letters forming the cells. Braille, it turns out,
was perhaps the first to incorporate the idea of data compression in human
readable form!
The six dots forming
the cell permit sixty three different patterns of dot arrangements. Strictly,
it is sixty four patterns but the last one is a cell without any dots and
thus serves the purpose of a space. A Braille cell is thus an equivalent
of a six bit character code, if we view it in the light of text representation
in a computer! However, it is not related to any character code in use
with computers.
Standard English
Braille
In standard
English Braille, many of the sixty three cells will correspond to a letter
of the Roman alphabet, or a punctuation mark. A few cells will
represent short words or syllables that are frequently encountered in English.
This is done so that the number of cells required to show a sentence may
be reduced, which helps minimize the space requirements while printing
Braille. These special cells are used in specific ways along with
regular cells to form sequences which are known as contractions.
Contractions are specified for most frequently used syllables and words
and there is a standard list of contractions in English Braille.
To begin with, one is taught Braille without contractions and this is called
Grade-1 Braille. Braille with contractions is known as Grade-2 Braille.
In standard Grade-1
Braille, the twenty six letters, and some punctuation marks are used.
No distinction is made between upper case and lower case letters.
Interestingly, numerals are not included in the set of symbols which have
been assigned cells. Shown below is the table that corresponds to Grade-1
Braille.
In the above
figure, only thirty six of the sixty three cells are shown. The rectangular
border around the cell has been added to make it easier for the reader
to identify the dots correctly. This border is not part of the definition
of a Braille cell and will not be seen in embossed documents. The cells
have also been arranged in some order which will be explained in a subsequent
page. A tutorial
on Braille explaining the basic principle of the six dot system will
be of interest to some of the readers.
Try reading
the following sentence shown in Grade-1 Braille! Use the table above for
reference.
Embossed
Braille
A sheet of Braille
has been standardized to a size of approximately 11 inches in width and
height, consisting of forty cells on each line and about twenty five lines
on a page. A sheet holds about a thousand cells (characters of text)
but in practice, when contractions are used, more text can
be accommodated. The
link below has some useful information on the dimensions for standard Braille
cells and sheets.
http://dots.physics.orst.edu:80/gs_layout.html
The image below shows a portion
of a sheet of embossed Braille. On a 1024x768 screen, the size of the cells
will be very close to the dimensions as per the Braille embossing standards
in use in most countries.
The
text printed in Braille in the above image is in the Tamil language.
Today, Braille embossers
can emboss Braille on both sides of a page. The dots on the reverse side
of the page form depressions on the page in front and hence will not be
felt while reading with the fingers.
The first image on this page
also shows the dots embossed on the reverse. The dots on the reverse will
be shifted and embossed without interfering with the dots on the front
side.
Braille
as a script
Braille may also
be viewed as a script built upon primitive shapes which are dots positioned
on a grid. In conventional scripts the letters are drawn using primitive
shapes which are stroked. The Braille cells cannot be reckoned as equivalent
to the strokes but each cell corresponds to a letter of the alphabet or
a special symbol used in writing a language. Hence Braille cells have to
convey different information in different languages. That is, the interpretation
of a Braille cell will be language dependent. Generally, countries of the
world have assigned the letters of their languages to specific Braille
cells according to their local requirements. For an interesting discussion
of Japanese Braille look at the link below.
http://buri.sfc.keio.ac.jp/access/arc/NetBraille/etc/brttrl.html
It must be noted
that Bharati Braille (the Braille scheme adopted by India and some South
Asian countries) has taken the best approach to presenting Indian language
text through conventional Braille by using phonetic equivalents from standard
English Braille to the extent possible. However, since there are only 63
different combinations available, only the basic vowels and the consonants
of the Indian languages, which are about fifty in number, have been accommodated.
Medial vowel representations are not possible and in Bharati Braille, one
just writes the consonant followed by the vowel ad this is acceptable as
a representation for a syllable. It is easy however, to get tuned
to this system of writing and visually handicapped persons seem to have
little difficulty in using this scheme. We
have included a discussion on Bharati Braille, its genesis and its implementation
for Indian languages.
Given below is an
image of a text string in Devanagari followed by its representation in
Bharati Braille.
As of now, Bharati
Braille does not incorporate the equivalent of contractions for all Indian
languages. For Hindi, Marathi and Gujarati, some contractions have been
recommended, though there is a proposal for contractions in other languages
as well. So Bharati Braille is effectively Grade-1 Braille at this
point of time.
Braille
and Computers
With the advent of
computers preparation of Braille documents has been rendered easy and flexible.
In the earlier days, Braille had to be printed using special Braille Printing
units that worked more like typesetting printing presses. Computers have
rendered the process simple where the required text can be typed normally
on a computer terminal and automatically transcribed into Braille and printed.
Transcription software will be language dependent but the rules of transcription
can be programmed for each language. Bharati Braille may also be transcribed
using computer programs by typing in the text in the vernacular. Software
developed at IIT Madras may be used to advantage here.
Computer
Braille (ASCII Braille)
To print Braille using
a device connected to a computer, the data corresponding to the cells has
to be sent to the device, usually called the embosser. The cells
have to be associated with some codes for this purpose. This scheme is
known as ASCII Braille. In this scheme, each braille cell will be specified
by an ASCII value which will not be the same as the English character or
the symbol the cell represents. When transcribing text to Braille, the
Braille codes corresponding to the letters of the alphabet and special
symbols are used. But when printing Braille,
the transcribed text is
mapped aagin into ASCII Braille before being sent to the embosser. ASCII
Braille is discussed further in a separate page.
Braille
output using the IIT Madras Software
The
IIT Madras software has taken a phonetic approach to representing Indian
Language text and so it is quite easy to convert the text prepared using
the Multilingual editor into Braille codes. Just a simple table look up
procedure is all that one would require and the program will convert text
in the vernacular (a .llf file as prepared with the editor) into appropriate
Braille codes for use with an embosser connected to a computer.
IIT Madras
has made such a utility program available though it is not included in
the editor package. This utility, called llf2brl works under Dos, Windows
and Unix and converts a .llf file (generated by the multilingual editor)
to produce a text file that could be sent directly to the braille embosser.
The llf2brl utility is command line based and will work properly under
Windows as well as Linux. An added advantage of this utility is that
it can prepare a file for subsequent processing with nfbtrans, a free transcription
utility from the National Federation of the Blind, USA. It will be possible
for one to prepare a bilingual Braille documents where Bharati Braille
will apply to text in Indian languages while standard Grade-2 translation
will apply to text in English.
Additional
information about this utility is available.
Preparation of training material for trainers
Useful information
by way of training material for the Visually Handicapped may be prepared
using the IITM multilingual editor. Documents for personnel who will train
the handicapped persons may be prepared in multilingual fashion, converted
to Bharati Braille on the fly and the resulting file formatted using transcription
software already in use for standard Braille. On-screen proof reading
may also be done with ease using fonts incorporating the Braille cells.
Such a font is freely available and may be downloaded from the site
referred to in this link. The page you are viewing was prepared
in this fashion.
Braille
Reference Links
http://www.nfb.org/emptrn/tech.htm
(Technologies useful for
the Blind)
http://www.nyise.org/access.htm
(page relates to applications
with accessibility features)
http://www.nea.gov/resources/Accessibility/AccessLinks.html
(Useful Accessibility related
link)
http://www.nyise.org/braille.htm
(Blindness Resource center.
Braille on the Internet)
http://www.braille.org/papers/lorimer/title.html
(Doctoral thesis relating
to the History of Braille)
http://www.braille.org/papers/index.htm
(Papers relating to Braille:
Scholarly issues like perception, learning Braille etc.)
http://www.uronramp.net/~lizgray/links.html
(Alternate link for Liz
Gray's references)
http://blindreaders.info/aids.html
(General reference on aids
for the blind)
http://www2.edc.org/NCIP/
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Contents
Introduction
The Braille
cell
English
Braille
Embossed
Braille
Braille
as a script
Braille
and computers
IITM Software
(Braille utilities)
Related
information
A
tutorial on Braille
This tutorial introduces
the system of Braille codes used for English and provides the basis for
the assignment of codes.
Introduction
to Bharati Braille
The principles of Bharati
Braille are presented in this tutorial
Online
Braille Quiz
Take an online quiz and
test your understanding of Braille codes. This quiz is on standard English
Braille.
A similar quiz is available
for Bharati Braille in different Indian languages.
Sanskrit/Hindi
Tamil
Telugu
Kannada
Malayalam
Web
Sites
Excellent discussions
on the basic principles of Braille are available at many web sites. These
are usually included in different sites providing information for the Visually
Handicapped.
The following sites are noteworthy
for their presentations and are hence well known.
Liz
Gray's pages
RNIB
(Royal National Institute
for the Blind, UK)
Additional links are included
at the end of the column at left.
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