DOTSPLUS: HOW-TO MAKE TACTILE FIGURES AND TACTILE FORMATTED MATH

Mark Preddy, John Gardner, Steve Sahyun, Oregon State University and Dave Skrivanek, Repro-tronics Inc.

Web Posted on: December 12, 1997

1. Introduction

Computer technology has made it possible, often quite straightforward and inexpensive, to make words accessible to blind people.[1] 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 a great challenge.[2,3] Some are almost impossible to make accessible.

The DotsPlus paradigm[4-6] is designed to overcome these difficulties. It allows a sighted person to make accessible hard copy materials involving line graphics and virtually any type of text. Standard Windows or Macintosh software 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 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. This expectation is realized in some instances but certainly not all. Haptic perception is far less capable than visual for distinguishing subtleties, so DotsPlus cannot be a panacea that can magically make every visual image totally accessible.

Initial testing by blind professionals and students has shown DotsPlus to be very useful for math equations and scientific text and for many 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

The greatest difficulty presented by the DotsPlus philosophy is that a huge number of different symbols is required - and 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 most particularly, cannot be easily distinguished tactually when represented as raised images. Consequently letters, numbers, Greek letters, and a small number of other symbols (e.g. the infinity sign, the at sign) are represented by braille cells.

The lower case alphabet is represented by the common dot patterns used in all languages using the roman alphabet. Upper case letters are represented as an 8-dot braille cell 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. Use of this kind of "mode-changer" violates the DotsPlus philosophy and would be almost impossible to implement. The dot patterns used for The American math or computer code "dropped letter: numbers cannot be used in DotsPlus for the same reason braille punctuation marks cannot. Therefore we have adopted the braille dot patterns used to represent numbers in the European computer codes. These patterns 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.)

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.

The average American literary braille reader should have little difficulty reading words. Eight dot capital letters may be unfamiliar, but they have proven quite easy to adapt to. Standard DotsPlus text reads very much like uncontracted (grade 1) literary 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 "feel like numbers" to most Americans But they are not hard to figure out when encountered.

4. How to make DotsPlus documents

Nearly any Windows or Macintosh application can be used to make DotsPlus documents. In order that the final printout have the right character spacing, use of 25 point DotsPlus-sighted[7] fonts is recommended when preparing the document. DotsPlus-sighted fonts are slightly-modified Courier and math fonts.

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.

The final version of the document can be viewed by switching the DotsPlus-sighted fonts to DotsPlus- tactile fonts. These latter are the same size as the DotsPlus-sighted fonts but have the dot representation of all characters represented in DotsPlus by braille.

Until recently, the most serious problem with DotsPlus was in transferring the DotsPlus-tactile picture on the video screen to a tactile pattern on paper. The only practical method has been through use of swell paper - a specially-coated paper onto which one transfers the image and passes through a radiant heater. When properly controlled the heater causes any portion of the paper that is black to swell and the white areas to remain smooth. Unfortunately the paper was not pleasant to read, was expensive, and the devices needed for printing and heating were extremely expensive.

During the past few years, Repro-tronics has introduced higher quality lower-priced "Flexi-paper" swell paper and has also introduced the moderately-priced Thermal Image Enhancer to process it. Some computer printers can print directly on Flexi-paper, but most computer printers produce enough heat that the white areas become at least slightly textured. Most fast copiers can copy to Flexi-paper, so it is generally most satisfactory to print the image onto regular paper using any convenient computer printer. Then this is copied to Flexi-paper, and it is processed through the Thermal Image Enhancer. We recommend that the DotsPlus-sighted font image also be printed and attached to tactile DotsPlus documents in order to facilitate easy communication between the blind reader and sighted friends, teachers, etc.

At the conference, a few DotsPlus pages made using a tactile graphics embosser were shown. This embosser is under development at Oregon State University. It embosses excellent braille intermixed with high-resolution dot-graphics. It can also emboss smooth vertical and horizontal lines. Information on the cost and date of commercial availability is presently not available.

5. Converting Documents to DotsPlus

A significant problem for blind students and professionals is access to non-textual materials originally prepared for sighted people. When paper copies only are available, the conversion process is painful and labor-intensive. One must scan images, use optical character recognition and/or replace text pictures by proper fonts in an appropriate computer software application.[3]

When the original electronic files are available, a far simpler conversion process may be possible however. The file must be loaded into the application from which it was generated, then converted to DotsPlus.

Generally the conversion process proceeds as: change all fonts to DotsPlus-sighted fonts, edit so the resulting documents will fit onto the eventual printout, edit and enlarge graphic images as appropriate, and then change to the DotsPlus-tactile fonts for printing on swell paper.

This procedure should work well for all applications using the standard Windows or Macintosh fonts. Most do. Normally the most serious difficulty is editing documents so that the information fits on the printed copy after the (approximately 2.5 times) enlargement to 25 point fonts.

We have made up a set of macros[7] that facilitate the conversion process for Microsoft Word.[8] One macro changes all fonts in the main document to DotsPlus-sighted. Another macro changes everything to DotsPlus-tactile fonts. Word automatically reformats for proper word wrap, and little or no editing is necessary in many cases.

Unfortunately any math expression created with the Word math editor is unaffected. Another of our macros allows one to go to each math expression in turn, open the math editor and change fonts, close the math editor, then go to the next math expression, etc. This procedure is a bit boring if the document contains many separate math expressions, but there presently seems to be no easier alternative.

The "fence fonts", from which large enclosures and some symbols (e.g. integral sign) are created by the math editor, are internally controlled by the editor and cannot be changed. However in 25-point, tactile recognition of these fence fonts is only slightly more difficult than it would be with more optimal shapes. The next release of the Math Editor is supposed to permit much easier font conversion and access to all fonts.

6. Acknowledgments

The research at Oregon State University was supported by National Science Foundation grant HRD- 9452881.

7. 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] The DotsPlus-sighted and DotsPlus-tactile fonts as well as the Microsoft Word macro package may be electronically retrieved following instructions on the Science Access Project web site at http://dots.physics.orst.edu or obtained from any of the Oregon State University authors.

[8] Microsoft Word is a registered trademark of Microsoft Corporation.