Non-visual access to non-textual information presents many challenges.
One challenge is that there are many examples of information in
which the content and visual layout are almost inextricably tied
together. When a clear separation of content and presentation
is possible, a second challenge arises - there are few electronic
formats that actually make this separation. A final challenge
is that of finding efficient, intuitive, inexpensive methods of
displaying nontextual information nonvisually. Two research programs
at Oregon State University that address some of these challenges
are described in this paper. One is the development of the DotsPlus
tactile font set and TIGER (TactIle Graphics EmbosseR). The second
is use of VRML to produce audio/tactually accessible 2D figures.
Keywords:
DotsPlus, tactile graphics embosser, VRML nontextual information, print disabilities
Speech or braille screen readers can provide excellent access
to standard computerized text (although access can be severely
hindered by complex electronic formats such as the PDF information
provided for potential presenters at this conference). Very little
other computerized information can be accessed easily (Barry 1994).
This paper discusses briefly two nontextual information access
research projects underway at Oregon State University. Each is
an attempt to find a general solution by defining or extending
current paradigms for display or data storage.
DotsPlus
DotsPlus is a paradigm for representing text tactually in one
of several fonts. Each character is unique and recognizable out
of context. These characteristics permit DotsPlus to be used in
graphics applications where text may appear in unpredictable locations.
Examples include mathematical equations, and labels or other text
notations on diagrams, maps, charts, etc.
The original DotsPlus font represented letters in 8-dot braille
(Gardner 1993) Subsequently a number of improvements were made,
in particular to the original punctuation marks, and a 6-dot DotsPlus
font was developed (Gardner 1998). Lower case letters are standard
braille in both font sets. A number of other symbols are also
represented in braille but most of the thousands of symbols appearing
in specialized literature are represented by tactile images of
the ink print symbol.
In 8-dot braille and DotsPlus, capital letters are indicated by
a dot in the dot-7 position (left bottom dot in a cell having
four rows and two columns of dots). In 6-dot braille and DotsPlus,
capital letters are indicated as a double width 6-dot cell. The
right side of that cell is lower case braille, and the left side
is the capital letter indicator. In English braille and DotsPlus,
the capital indicator is a dot in the lower right position.
DotsPlus numbers are represented by European Computer Braille,
and punctuation marks are represented by graphic symbols that
feel much like braille punctuation marks but are distinguishable
from dropped letters if examined carefully.
We believe that most literary braille readers who want to learn
DotsPlus can do so rather easily. Apart from the numbers, standard
text reads very much like uncontracted braille. A DotsPlus reader
of more advanced literature must learn many new symbols, but this
is identical to the learning process of sighted readers. A blind
or sighted child must both learn the shape of a plus and equals
sign before learning to do arithmetic for example.
There are only minor differences between DotsPlus fonts among
languages sharing the roman alphabet. In 8-dot DotsPlus, the period
(full stop) symbol shape may be altered for languages (e.g. German,
Swedish) having a different braille period from the English/French
symbol. For 6-dot DotsPlus the "prefix" symbol in the
double cell braille symbols can be changed to reflect different
capital letter indicators used in languages other than English.
Such differences are minor enough that readers should have little
difficulty reading literature printed in other languages. This
is unfortunately not true for most braille literature.
Widespread testing and use of DotsPlus has been severely hindered
by the difficulty and expense of printing DotsPlus. A wax-jet
printer used for original DotsPlus research is no longer commercially
available. Swell paper can be used to make DotsPlus materials,
but swell paper is expensive and requires considerable expertise
to make copy in which braille dots are easy to read.
A new technology invented at Oregon State University now allows
embossing with resolution good enough to make DotsPlus materials.
The TIGER printer, based on this new technology, is expected to
become commercially available at a cost of approximately $6000
by the time of this conference. The TIGER includes a Windows 95
printer driver that permits direct printing from most Windows
95 applications. Users need to use a screen font with the correct
size and should avoid complex multicolored or gray scale drawings.
Otherwise virtually anything that can be printed on a standard
printer can be printed on TIGER.
Accessible Graphics using VRML
Virtual Reality Modeling Language (VRML) is becoming popular in
World Wide Web applications (Roehl 1996, Carey 1997). VRML allows
one to create time-dependent three-dimensional models that can
be displayed interactively. VRML "figures" are electronic
files organized into a well-structured tree and are displayed
by viewers that provide a two dimensional projection of the model
(VRML 1997). Users may interactively modify the view by turning
or moving through the model.
We have taken advantage of the power and flexibility of VRML to
construct and display simple two dimensional figures such as those
appearing in scientific literature at all levels. (Bulatov, 1998)
We construct a VRML model using any convenient three dimensional
objects whose projection is the 2D picture we desire. This may
be done with standard authoring tools and eventually with a special
2D authoring tool we intend to write. This model is then modified
with a special editing software application we have designed.
With this editing software one may produce a second VRML file
in which each object can be provided with a label that contains
information that is, in principle, arbitrarily rich. Presently
we permit only plain text.
Standard VRML browsers display the second file identically to
the first. However if the model is well structured, and the labels
are sufficiently informative, the second VRML figure is completely
accessible to people with print disabilities through one of a
number of specialized "viewers".
The special viewers are programs that supplement a standard VRML
viewer by interpreting the special labels. The simplest special
viewer, and the only one that is near completion at present, uses
a common technique that permits a blind user to "read"
a complex tactile figure with the help of a computer. A tactile
copy of the VRML picture must be made and placed on an external
digitizing pad. A blind user may then explore the tactile figure
and request information about objects. This request, made for
example by pressing on an object and activating the digitizing
pad, causes the label to be displayed on the computer screen and,
if desired, browsed in audio through use of an internal speech
engine. In principle the label can be read with a braille or speech
screen reader also.
The "audio/tactile" viewer has the disadvantage that
a tactile copy must be printed before the figure can be read.
An external digitizing pad is also required. Many kinds of information
can be displayed by simpler schemes in which some kind of on-line
tactile or audio object locator gives the user qualitative or
semi-quantitative information about the position and shape of
objects in the model. Then the user can choose to display the
label for more information. We note that a three-dimensional object
locator that a blind user can use to follow an object would open
the possibility of access to nearly any VRML model, not just 2D
projections. Finally, there are classes of information (e.g. structured
trees, flow diagrams, charts, and tables) for which a user may
find it more convenient to explore logical structure rather than
physical structure.
These are all possible in principle, but a considerable amount
of research and testing is required to learn how to translate
these concepts into useful products. The special accessible VRML
format we have developed permits this type of research.
The purpose of this research project is to make 2D graphics accessible to people with print impairments, not specifically to make VRML accessible. However VRML is presently the only public format that is both well-structured and flexible enough to permit addition of labels. VRML models of the future could, in principle, be made fully accessible by the authors if they choose to add sufficiently detailed labels. Alternatively, it is relatively straightforward for an editor later to add labels to a well-designed existing VRML model. To our knowledge no other 2D or 3D graphics format permits either possibility. These two properties, along with the existence of a number of user-specific special viewers make the VRML format potentially quite accessible.
This research was supported in part by the National Science Foundation
under grants HRD9452881 and HRD9353094.
| Barry, W. A, Gardner, John A, and R. Lundquist | 1994, "Books for Blind Scientists: The Technology Requirements of Accessibility", Information Technology and Disabilities, 1(4), 1994. Also available at http://www.rit.edu/~easi/itd/itdv01n4/article8.html
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| Bulatov, V. | (1998) Several examples of accessible VRML figures are given in the discussion at http://dots.physics.orst.edu/vrml/
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| Carey, Rikk and Bell, Gavin | (1997) "The Annotated VRML 2.0 Reference Manual" (ISBN: 0-201-41974-2 ) |
| Gardner, John A. | 1993 "DotsPlus - better than braille?", John A. Gardner, published in Proceedings of the 1993 International Conference on Technology and Persons with Disabilities, Los Angeles, CA, March, 1993. Also available at http://dots.physics.orst.edu/publications/csun93.html
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| Gardner, John A. | 1998 "DotsPlus" http://dots.physics.orst.edu/dotsplus.html
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| Roehl, B. | (1996). VRML: A Standard for Virtual Worlds. Virtual Reality Special Report, 3(3), pp. 14-18. |
| VRML97 (ISO/IEC 14772) | International Standard - http://www.vrml.org/Specifications/
|
John Gardner directs research programs in both Materials Physics
and Information Access technologies. The latter was undertaken
after losing his sight in 1988. His research is funded by the
US Department of Energy and the National Science Foundation. He
has won a number of prizes for excellence in both research fields.