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Improving access to hypertext based study material for the blind

ABSTRACT

This paper explains the services provided and the current projects at the Dresden University of Technology. The primary goal of the projects is to make study material accessible to blind and partially sighted students by using structured hypertext based document formats.

The paper describes, how it is possible to convert study material, coded in a less structured ASCII format, into HTML, by using the basic SGML tag set for accessible documents as defined by ICADD (International Committee for Accessible Document Design). This transformation guarantees the accessibility of the documents available on the World-Wide Web.

Furthermore, the Transformation Services for HTML documents into American, French and German Braille, available on a WWW server (URL: http://elvis.inf.tu-dresden.de/) is explained. This service was developed by using the ICADD guidelines to translate SGML documents into Braille, large print and computer voice, published in appendix 8 of the international standard ISO 12083.

The final part of the presentation describes our current project which is to design and implement an accessible hypertext script reader for SGML based study material. This reading program will establish access to documents, which are widespread over the network, for blind and partially sighted students. The handling of tables and the design of hypertext structures in documents are the main challenges in this project.
Table of Contents

1 Introduction
2 Preparation of accessible study material
3 Transformation of ASCII documents into HTML
4 Transformation of HTML documents into American, French and German Braille
5 Hypertext reader for SGML based study material

1 Introduction

This paper explains the services provided and the current projects at the Dresden University of Technology. The primary goal of our projects is to make study material accessible to blind and partially sighted students by using structured hypertext based document formats.

To improve access to ASCII text based study material the documents will be converted into HTML (Hyper-Text Markup Language) [1], the most commonly used format in the WWW (World-Wide Web) [2]. HTML V. 2.0 is basically a DTD (Document Type Definition) described in SGML (Standard Generalized Markup Language) [3], a document architecture which is increasingly used by the electronic publishing industry. The advantage of using SGML based document formats to improve the quality of electronically available reading material for print disabled persons is described in presentations about the EU Projects CAPS and HARMONY [4] and in our report "A Journal Header Reader for the blind", [5] presented at the SGML Europe conference in May 1995.

The HTML DTD provides structured markup to represent text based documents with the capability to handle hypertext links. Actually, the facilities to markup tables and mathematic expressions are under development by the IETF (Internet Engineering Task Force) HTML working group.

2 Preparation of accessible study material

The usual preparation of accessible study material starts by scanning printed material and the optical character recognition of the electronically stored images provided by special software. The result of this process is a unstructured ASCII text file, which needs to corrected manually.

If the printed document contains tables, mathematic expressions, graphics or pictures, the person who corrects the data has to use special guidelines to describe the information in a textual form.

The guideline (Tutorenanleitung - zur Umsetzung sehgeschädigtengerechter Studienmaterialien) [6] designed at the Universities of Karlsruhe and Dresden describes the following rules:

  • the general structure of an accessible document,
  • how to set up tables in textual form and
  • how to capture and describe graphic information and pictures.

Mathematic expressions have to be specified in a particular notation called AMS (ASCII Mathematik Schrift) [7], which uses a programming language like syntax of ASCII characters to linearize this kind of information.

Example AMS01 (A Simple fraction): y = (x+1)/(x-1)
Example AMS02 (An Integral): y = Int[a;b] f(x) dx


Blind and partially sighted students in Dresden do have access to the prepared documents by using adaptive PC's in a local area network. The file service which stores these documents is called ELVIS (Elektronisches Literatur Verzeichnis für Sehgeschädigte) [8].

Most of these documents provide less structured information, which makes searching and linking for particular data difficult for the user. It became clear to our group, that a platform independent structured hypertext system might be able to improve the access to the documents. The increasing use of the WWW and HTML appears to be the right starting point.

3 Transformation of ASCII documents into HTML

To make study material accessible over the WWW, we developed a transformation service for ASCII text documents into the HTML V. 2.0 format. This transformation is implemented as a batch process on a UNIX platform. The transformation of the data is divided into the following steps:

STEP 1: ASCII to ICADD
In the first step, the ASCII text files are converted into a format according to the ICADD22 DTD [9]. This DTD provides a basic set of SGML elements necessary to markup a document structure which is accessible to print disabled persons. This particular set of markup, designed by the ICADD (International Committee for Accessible Document Design), provides easy access to the general document structure in translating the data into different formats e.g. Braille, large print and computer voice.
STEP 2: ICADD to HTML
In the second step of the transformation the ICADD data are converted into the HTML V. 2.0 format. To keep the whole document accessible, tables are represented as plain text in HTML. The reason in handling the data in a particular way is due to the fact that text oriented Web browsers like LYNX [10] currently do not support the HTML markup for tables [11].

Mathematic expressions, which are given in the AMS notation, are not changed during the conversion process. This kind of data remains in the format and can be read by using text oriented Web browsers.

4 Transformation of HTML documents into American, French and German Braille

To improve access to the WWW, for persons who are print disabled and can read Braille, we developed a form based transformation service for HTML documents into American, French and German Braille. This service is designed by using the ICADD guidelines for the transformation of SGML documents into accessible formats for print disabled persons, published in the Appendix 8 of the standard ISO 12083 [12].

The idea of this project was initiated by the "HTML to ICADD Transformation Service" at the University of California, Los Angeles, developed by Jeff Suttor [13].

The TU Dresden "International HTML to Braille Service" extends the idea, to convert Web pages into Braille, from one - into three languages. The transformation of the documents into the different Braille notations is designed by the use of the German HBS software [14].

The service can be initiated, by filling out and submitting the online form, available at:

A user can specify an URL (Uniform Resource Locator) [15], that points to a document, which has to be translated by the service. Radio buttons can be used for the choice of the appropriate Braille formats. The following Braille formats are available:

  • German contracted Braille
  • German uncontracted Braille
  • French uncontracted Braille
  • American uncontracted Braille

After submitting the form, the specified document will be translated automatically into the chosen Braille format and displayed by the browser. The received document can be read immediately or saved on a local file for later use.

5 Hypertext reader for SGML based study material

Our current project "Präsentation von elektronischen Dokumenten für blinde Menschen" [16] is designed to establish access to hypertext based study material for blind students. By developing a SGML based Script Reader, we would like to make our prepared study material accessible by using the WWW. The Script Reader will run on MS-Windows 3.X and will be implemented by use of a particular SGML browser engine ViewPort [17]. This software was developed by the Swedish company SYNEX and is used in the SGML browser PANORAMA [18] from Softquad Inc.

The Script Reader will provide the following features:

  • Access to structured documents over the network
  • Hypertext navigation
  • Presentation of mathematic expressions in the AMS notation
  • Rendering of HTML tables into textual format

By using bridge software to make the graphic user interface accessible to the blind user, the Script Reader will offer the following functions in separate windows:

  • Document viewing
  • Table of contents
  • Tables rendering
  • History
  • Bookmarks

The window, which is activated, will use the full screen to display the information. By highlighting hypertext links, the user can trace and navigate through the given structure of a document. Tables will be treated in a separate window by using a particular table browser. This browser will render less and complex structured tables in different ways. This method will allow us to evaluate the first results of this project and to improve future versions of the reading program.

The system will not provide functions to edit or manipulate the documents. But the user can extract and save information in private note - or bookmark files. The history function can be used to trace particular information and to memorize document ancestries.

We hope, that the development of this Script Reader can be a moderate contribution in improving the access of electronically stored information for persons who are print disabled.


BIBLIOGRAPHY

[1] Request for comments, RFC 1866 Hyper-Text Markup Language V. 2.0, URL: http://www.w3.org/pub/www/
[2] W3C, World-Wide Web Consorcium, URL: http://www.w3.org/
[3] ISO, ISO 8879:1986 Information Processing - Text and Office Systems - Standard Generalized Markup Language (SGML), Geneva, 15 October 1986
[4] B. Bauwens, J. Engelen, F. Evenepoel, C. Tobin, T. Wesley
Structuring Documents: the Key to Increasing Access to
Information for the Print Disabled in: 4th International Conference ICCHP '94, Proceedings, Vienna, Austria, September 14-16, 1994, Springer-Verlag Berlin Heidelberg, 1994
[5] Th. Kahlisch, G. Vogel, A Journal Header Reader for the blind, SGML Europe'95 Conference, URL: http://elvis.inf.tu-dresden.de/~kahlisch/europe.html
[6] TU Dresden, AG Studium für Blinde und Sehbehinderte, Universität Karlsruhe, Studienzentrum für Sehgeschädigte, Tutorenanleitung - zur Übertragung
sehgeschädigtengerechter Studienmaterialien, 1995
[7] TU Dresden, AG Studium für Blinde und Sehbehinderte, Universität Karlsruhe, Studienzentrum für Sehgeschädigte, ASCII-Mathematikschrift für Blinde,
1993
[8] TU Dresden, AG Studium für Blinde und Sehbehinderte, ELVIS (Elektronisches Literaturverzeichnis - Infomatik für Sehgeschädigte), URL: http://elvis.inf.tu-dresden.de/
[9] ICADD, (International Committee for Accessible Document Design), Chair America: George Kerscher (kerscher@montana.com) Chair Europe: Tom Wesley (T.A.B.Wesley@bradford.ac.uk)
[10] University of Kansas, LYNX (text oriented Web browser), URL: ftp://ftp2.cc.ukans.edu/pub/
[11] IETF, HTML Tables Specification, URL: http://www.w3.org/pub/WWW/
[12] ISO, ANSI / NISO / ISO 12083 Electronic Manuscript Preparation and Markup, Annex 8: Facilities for Braille, large print and computer voice, 1994
[13] Jeff Suttor, HTML to ICADD Transformation Service, University of California - Los Angeles, URL: http://www.ucla.edu/ICADD/html2icadd-form.html
[14] HBS - Hagener Brailleschrift System, Fernuniversität Hagen - Gesamthochschule, Zentrum für Fernstudienentwicklung, Red. Fernstudium für Sehgeschädigte
[15] Request For Comment, RFC 1808 Relative Uniform Resouce Locators, URL: http://www.w3.org/pub/WWW/
[16] TU Dresden, Lehrbereich, Mensch-Maschine-Kommunikation ifS, Drittmittelprojekt: Präsentation von elektronischen Dokumenten für blinde Menschen,
URL: http://elvis.inf.tu-dresden.de/
[17] SYNEX Inc., ViewPort (SGML browser engine), URL: http://www.synex.se/
[18] SOFTQUAD Inc., PANORAMA (SGML browser), URL: http://www.sq.com/

Th. Kahlisch
am 22. Mai 1996