The following is forwarded for your edification with permission of Dr. John
Gardner. You will remember Johns presentation at our Texas convention.
That's funny! I can't remember the exact year that was, but I remember
everything he said.
You should also know that John is a powerful catalyst in current research on
Braille code and hardware development in the U.S. and Europe.
Tim Cranmer
**********
Preprint of paper to be presented at the
1994 International Conference on Technology and Persons with Disabilities,
and submitted for publication in the proceedings of that conference.
***** CSUN paper preprint
Accessibility to Scientific Information by the Blind:
Dotsplus and ASTER could make it easy
William A. Barry and John A. Gardner *
Department of Physics, Oregon State University
T. V. Raman
Department of Computer Science, Cornell University
Advanced scientific documents have historically been inaccessible
to the blind. The symbolic system normally used to express
mathematical and scientific ideas is more complex than the
letter after letter, word after word, line after line of regular
literature. This leads to difficulty when mathematics is
translated into Braille or when mathematics is spoken. Now that
more and more scientific documents are available in
electronic format, this difficulty can be remedied. We describe
two methods for displaying technical documents in a non-visual
format: ASTER, a system for reading aloud such documents, and dotsplus,
a tactual method of printing such documents.
Both ASTER and dotsplus address the fact that scientific
literature is usually presented to sighted readers in a
multi-dimensional format. It is multi-dimensional in the sense
that the information is contained not just in the words
themselves, but also in the positions of the words and in the
fonts used in printing the words. This multi-dimensionality
allows the reader to browse, recognizing the big structures
first and then focusing on particulars. For instance, it is
quite easy for a sighted reader to browse through a paper
and just read the bold-face section titles; or when reading an
equation containing a fraction with a complicated numerator and
denominator, the reader can notice at a glance that the equation
contains a fraction, then go back and read the numerator and
denominator.
ASTER
ASTER, an acronym for Audio System for Technical Reading, is a
software application that controls a voice synthesizer and an audio
soundboard. It takes electronic documents and reads them aloud
using the notion of audio formatting to express multi-dimensional
information. This audio formatting is accomplished by several
techniques:
1) Voice synthesizer parameters such as pitch and tone are
utilized so that not only the word has meaning, but also the way
the word is said has meaning; for instance, the math expression
x squared which is printed as x with a superscript 2 can be
spoken by ASTER first by saying x then saying 2 in a higher
pitch voice, the higher pitch indicating a superscript (in
contrast, a lower pitch would indicate a subscript).
2) The audio soundboard is used to create unique tones and other
non-verbal sounds which can be used to indicate the beginnings
of sections or paragraphs.
3) Stereo effects are used to make sounds appear in different parts
of space. This is useful for reading aloud tables where columns can
sound next to each other in space.
4) The reader may interactively change the rules governing the
way that something is read; for instance, x with a superscript 2
can be read "x squared" or it can be read "x super 2" or it can be
read "x 2", with the two being read at a higher pitch. Each reading
rule corresponds to a different view of the object being read.
The most common way that students currently receive technical
documents is as an audio tape of another person reading the
document. This presents a single view of the document in which
the only controls over the reading are the choices of the person
initially taping the document and the pause and fast forward
buttons on the tape-player. ASTER improves on this technique by
allowing multiple views of the document using different reading
rules and by allowing much finer control over the browsing.
ASTER's browsing mode allows the reader to step back and forth
and selectively read or re-read anything in the document. This
browsing along with the notion of reading rules allows the
reader to skim the document, for instance, reading all the
section titles or reading only the equations or reading the
first few words of each paragraph.
Since it is not easy to grasp and understand long complex
objects that are read aloud from beginning to end, ASTER has
one particularly useful reading rule which replaces complex
expressions in math equations with a single variable. For
instance a fraction with a very complex numerator and
denominator can be read aloud as "the fraction n over d where n
is such and such and d is so and so". In this way the reader
gets an overview of the main structures in the equation and
later is given the finer details.
ASTER works by first reading an electronic document and then creating
an abstract model of it. This model is display-independent, i.e., it
contains no explicit information about how to visually format or audio
format the document. It is instead a high level representation of the
information which can then be interpreted according to the instructions
built into ASTER or according to the instructions of the person reading
the document. Each document structure/element - such as a section or a
paragraph or an equation or a particular part of an equation, e.g., the
numerator of a fraction - is thought of as an object in this abstract
document model. After this model has been created, ASTER begins reading
aloud the document using a voice synthesizer and an audio sound
generator. As it encounters each object in the document model, it reads
that object according to the reading rule for that specific object.
These rules, written in the Audio Formatting Language (AFL), control
the order in which words are spoken, the voice synthesizer parameters,
and the audio soundboard. There are several pre-written rules from which the
reader may choose, or the reader may write his own reading rules to
tell the system how to read an object.
ASTER is currently implemented on a Sun Sparcstation IPC using a
Multivoice speech synthesizer and the Sparcstation's built-in audio.
It is written in the object-oriented language Common Lisp using
the CLOS extensions to Lisp. There are plans for this system to
be rewritten in C++ so that it can be ported to other platforms.
DOTSPLUS
Dotsplus is a tactile method of printing technical literature
for blind readers that incorporates both Braille and graphic
symbols in a manner that retains the same structure as a
document printed for a sighted person. Some of the more easily
recognized symbols such as plus, minus, the division line in
fractions, etc. are enlarged and printed as raised images, while
Braille is used for alphabetic characters, numbers, punctuation
marks and other symbols that are hard to recognize as raised
symbols. The placement of symbols and characters is the same in
dotsplus documents as it would be for a sighted person -
subscripts are dropped below and superscripts are raised above
the position of the main character; numerators of fractions are
placed above the denominators; in advanced equations, symbol
placement such as sum and integral limits, are preserved. Thus
dotsplus uses some of the same formatting that is used for
visual printing to convey information in a tactile format.
In standard Braille, all characters are in a straight line and that
line is denotes where the top and bottom of the Braille cell is
located. In dotsplus the characters are not necessarily in a straight
line. Thus, it is difficult to distinguish a dropped cell such as a
punctuation mark from a subscripted cell of another character. To avoid
this ambiguity dotsplus incorporates graphics into the dropped cells by
putting a solid line above and below the character. These solid lines
tell the reader that he is reading a dropped cell and locate the top
and bottom of the cell. There are other changes from standard Braille:
for example, the use of the numbers from European computer Braille and
the use of 8-cell characters instead of 6-cell characters. (For more
details on these changes, see our paper Dotsplus - Better than
Braille? in the CSUN 1993 Conference Proceedings.)
Dotsplus documents are produced using a set of Truetype or Postscript
fonts and are currently printed using a wax-jet printer that has been
modified to print a very thick layer of wax. We pass the paper through
the printer twice to get good quality raised images - a very tedious
process. However, the printer we use is no longer produced, so we are
therefore actively exploring other methods of printing.
Another important aspect of the dotsplus method is the incorporation of
graphics into the document. Many technical papers have drawings and
graphs in them. In many papers that are Brailled for students, these
drawings are left out and the student is instructed to ask the teacher
to explain them. In dotsplus these illustrations are incorporated
directly into the document. One method we use is to scan them in,
expand the drawing roughly by a factor of two, and then use a bitmap
image editor to replace any print characters in the illustration with
Braille/dotsplus characters. The illustration is then printed out in
raised mode along with the rest of the document.
In summary, both dotsplus and ASTER provide useful methods for presenting
math, science, and other technical documents. There are, however, a few
things that must happen before these two systems can be widely used.
For dotsplus, an appropriate printer must be designed; ASTER must be
ported to other computer systems. Also, both dotsplus and ASTER depend
on the availability of electronic documents in an appropriate format.
This leads us to a final discussion of the accessibility of documents.
Documents come in a hierarchy of accessibility. The most accessible
documents are those written using a markup language such as SGML or
TeX/LaTeX. In these documents, the objects are clearly labeled; for
example, a fraction in LaTeX is input as \fraction{n}{d} where n is the
numerator and d is the denominator, and the beginning of a section is
marked by \section{section name}. In order to print a LaTeX or SGML
document it is necessary to convert it into a language which the
printer understands such as PCL (the printer command language) or
Postscript, a so-called page description language. All printer
languages are designed to tell the printer only where on the page to
put a character and what font to use when printing it. To a page
description language, a fraction is just one character over another
separated by a line. Page description languages are inherently
visual in nature and contain no information about what they are
printing except to someone who can see the page. Only slightly below
the printer languages in accessibility is a piece of paper or its
electronic equivalent, the bitmap. To make these accessible requires
sophisticated optical character recognition software and as yet,
there is no optical character recognition software that recognizes
mathematical text. Therefore, when creating and distributing documents
the most accessible format is a markup language such as Tex/Latex or
SGML and the least accessible are page description languages such as
Postscript or PCL, or paper. Even an ASCII text is not as accessible as
a markup language because an ASCII text does not have its parts clearly
labeled. Thus, the current versions of dotsplus and ASTER work best
with TeX/LaTeX and could easily be made to work with SGML documents.
It is hoped that more documents in the future will be available in
these formats.
* Research program supported in part by the US National Science
Foundation.
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