1998 Conference Proceedings

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DOTSPLUS: A HOW-TO DEMONSTRATION FOR MAKING TACTILE FIGURES AND TACTILE FORMATTED MATH USING THE TACTILE GRAPHICS EMBOSSER

Steve Sahyun, Vladimir Bulatov, John A. Gardner, and Mark Preddy
Science Access Project, Dept. of Physics
Oregon State University
Corvallis, OR 97331, USA
http://dots.physics.orst.edu

1. Introduction

Computer technology has made it possible, often quite straightforward and inexpensive, to make words accessible to blind people.[1] However, making anything except words accessible remains a formidable challenge. Math equations, and figures such as maps, graphs, drawings, and charts that contain both graphics and characters (particularly those such as plus or equals that have no representation in standard literary braille) at unpredictable places pose great challenges.[2,3] Some items are almost impossible to make accessible to blind readers.

The DotsPlus tactile fonts[4-7] are designed to overcome some of the difficulties in making math and text in figures accessible. They allow a computer user to make hard copy materials involving line and block graphics and virtually any type of text accessible. Standard computer applications may be used, and little special training is needed by the preparer.

DotsPlus uses literary braille symbols where possible, so the reader does not need to be familiar with math braille or computer braille codes. A one-page "cheat sheet" of the most common DotsPlus symbols contains enough information for a literary braille reader to be able to read almost anything in DotsPlus short of truly arcane advanced math and science.

2. DotsPlus Philosophy

The philosophy of DotsPlus is to present tactile graphic material in essentially the same spatial layout that is used for visual material. Thus, text and labels may be included in arbitrary positions in graphic materials. In a mathematical expression, a superscript is raised and a subscript lowered, the numerator of a fraction is shown over the denominator with a horizontal fraction line between them, exactly the spatial layout used in an ink-print copy of the same expression. The expectation is that a blind reader will be able to achieve the same information from the layout that a sighted reader does.

Initial testing by blind professionals and students has shown DotsPlus to be very useful for math equations, scientific text, and for many other kinds of graphic information. Simple charts, graphs, flow diagrams, circuit diagrams, line-drawing illustrations, and similar line or block graphics are among the kinds of materials that can be made accessible using the DotsPlus philosophy.

3. DotsPlus Characters

DotsPlus fonts must include all essential characters of typography, math, and science. This is a very large list, and each character must be distinguishable out of context, since the position of a symbol on a DotsPlus page is not predictable, unlike normal braille where all cells are "on-line".

Consequently, most symbols are represented in DotsPlus as tactile graphic images shaped like the visual symbol. The plus, minus/dash, equals, times (cross), and divide symbols are raised images. So are parentheses, brackets, braces, and more exotic math symbols such as integral, product, and sum indicators. Some symbols, letters and numbers in particular, cannot be easily distinguished tactually when represented as raised images. Therefore, letters, numbers, Greek letters, and a small number of other symbols (e.g. the dollar, number/hash, ampersand, and at sign) are represented by braille cell symbols.

The lower case alphabet is represented by the common dot patterns found in all languages using the roman alphabet. Upper case letters are represented either as an 8-dot braille cell or a double six dot cell. The six dot representation is conventional six dot English braille, and the eight dot cell is constructed by adding a dot on the left side of a row below the representation of the lower case letter. This is a convention adopted on all modern 8-dot braille computer displays and braille printers.

Punctuation marks are represented by tactile graphic images that have very similar shapes to the braille literary punctuation marks. It is necessary to use graphic images because the braille representations of punctuation marks cannot be distinguished from letters out of context. By using graphic images that feel very much like standard braille punctuation marks, a reader familiar with literary braille will usually know from context whether the symbol is a punctuation mark or a displaced letter, so the reader will only occasionally have to feel carefully to distinguish the difference.

In literary braille, the numbers 1-9, 0 are represented by the letters a-j in a string preceded by a "number" sign. Computer fonts must have unique characters for numbers, so literary braille numbers cannot be used in any tactile font. Computer braille codes are fonts, but the braille numbers used in the American Computer Braille code cannot be used as DotsPlus numbers. American computer braille numbers are the same as the "Nemeth" numbers (dropped letters) used in the American math braille code and cannot be distinguished from letters out of context or position. Since the braille dot patterns used to represent numbers in the European computer codes are unique representations, they have adopted for use in DotsPlus.

The dot patterns of European computer braille numbers are unambiguous out of context. The digits 1 to 9 are formed by adding a dot in the sixth dot position (lower right of a 6-dot cell) to the letters a-i. The zero is similar to a braille j but with the bottom row dropped. (The rule for forming zero must be different in order to avoid conflict with the letter w.) These braille symbols are contractions in English braille and conflict with nothing in the uncontracted (grade 1) braille code or other DotsPlus symbols.

In eight-dot DotsPlus, Greek letters are expressed as 8-dot braille cells having a dot on the extreme lower right. The upper portion of these cells is the same as the final cell used for Greek letters in all math braille codes. In six-dot DotsPlus, Greek letters are represented by double cells having a dot-46 as the first cell for lower case, and a dot-456 for upper case.

The average American literary braille reader should have little difficulty reading DotsPlus words and punctuation, since these feel like Grade 1 braille. The reader must of course learn the shapes of the graphical symbols, just as a sighted reader does. The most significant learning curve will probably be the number representation. These numbers will not initially "feel like numbers" to most Americans But they are not hard to figure out when encountered. Motivated Europeans have learned the computer code, including these numbers, within a matter of a few weeks.

4. Printing DotsPlus with the TIGER

DotsPlus was originally developed and tested using a wax-jet printer that is no longer commercially available. Until recently the only way to print DotsPlus was through use of swell paper[7].

The TIGER[8] (TactIle Graphics EmbosseR) makes DotsPlus extremely straightforward to print. TIGER has a Windows 95 printer driver that permits tactile printouts from almost any application that supports printing. Screen fonts properly sized for printing either six- or eight-dot DotsPlus are provided with TIGER. TIGER automatically converts these fonts to DotsPlus when printing.

A demonstration will be given using MS Word and CorelDraw for writing documents involving math, maps, flow diagrams, and/or other common materials requiring both text and graphics. In the demonstration, MS Word six-dot DotsPlus and eight-dot DotsPlus templates will be used to write several documents that will then be printed on a TIGER. The same file may be printed with any standard ink-print printer to obtain a copy readable by sighted peers, teachers, or relatives of the blind user. A universally-readable copy may be obtained by printing the braille paper in an ink printer and then printing with the TIGER. The same computer document is just printed twice, once with an ink-printer and then with TIGER.

Line graphics should generally be larger than what would be made for a person with good sight. And fancy, highly-detailed graphic images are likely to be difficult for a blind person to interpret. Roughly speaking, a simple elegantly-designed line graphic composition that a sighted person can understand easily should also be understandable by the blind reader provided the images are not too small.

More complex graphs an charts can be simplified by separating the information of one picture, and creating a series of images. This has been particularly useful when representing a 3-D image as a series of pages of 2-D images. With TIGER and DotsPlus, this process is simplified, as standard vector drawing programs (such as CorelDraw, and the Drawing functions in Word) produce clean, detailed images with unambiguous text. If more textual information is needed than can be conveniently displayed within an image, DotsPlus has a special character representing a tag. So, when a tag character is used, a list can be made below the image with the text at the tagged point.

5. Acknowledgments

This research was supported by National Science Foundation grant HD-9452881.

6. References

[1] Information on technologies for making words accessible to blind people is available from many sources. We recommend the organization Equal Access to Software and Information (EASI). Their world wide web site has a wealth of information and pointers to many sources of data and information. The URL is: http://www.rit.edu/~easi/

[2] John A. Gardner, "TACTILE GRAPHICS: AN OVERVIEW AND RESOURCE GUIDE" in Information Technology and Disabilities, Vol. 3 No. 4, December, 1996, http://www.rit.edu/~easi/itd/itdv03n4/article2.html. Also available as a highly-hyperlinked document at: http://dots.physics.orst.edu/tactile/tactile.html

[3] David Schleppenbach, "TEACHING SCIENCE TO THE VISUALLY IMPAIRED", in Information Technology and Disabilities, Vol. 3 No. 4, December, 1996, http://www.rit.edu/~easi/itd/itdv03n4/ article1.html

[4] Up-to-date information about DotsPlus is maintained on the Science Access Project web site: http://dots.physics.orst.edu

[5]John A. Gardner, "Dotsplus-Better than Braille?", Proceedings of the 1993 International Conference on Technology and Persons with Disabilities, Los Angeles, CA, March, 1993. Available at: http://dots.physics.orst.edu/csun93.html

[6] W.A. Barry, John A. Gardner and T.V. Raman, "Accessibility to Scientific Information by the Blind: Dotsplus and Aster could make it easy", Proceedings of the 1994 CSUN Conference on Technology and Persons with Disabilities, Los Angeles, CA, March 1994. Also available at http://dots.physics.orst.edu/csun94.html

[7] M. Preddy, John A. Gardner, S. Sahyun, and D. Skrivanek, "DOTSPLUS: HOW-TO MAKE TACTILE FIGURES AND TACTILE FORMATTED MATH", Proceedings of the 1997 CSUN Conference on Technology and Persons with Disabilities, Los Angeles, CA, March 1997

[8] TIGER was invented and developed in the Science Access Project. ViewPlus Technologies has been licensed to manufacture TIGER. ViewPlus Technologies has a booth at the 1998 CSUN Conference and will be taking orders for delivery of TIGER beginning in summer 1998.


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