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Information Technologies for Visually Impaired People
SAW: a Set of Integrated Tools for Making
the Web Accessible to Visually Impaired Users
Fernando Sánchez-Figueroa, Adolfo Lozano-Tello, Julia González-Rodríguez, Mercedes Macías-García
In this paper a System for Accessibility to the Web (SAW) for visually impaired people is introduced. SAW consists of a set
of integrated tools designed to be used by both Web designers and end users. The foundation of SAW is an ontology that
allows the definition of the entire set of elements that can belong to a Web page. This ontology also represents the relationships
between elements and the accessibility attributes of elements and relationships. From the point of view of the designer,
an editor is provided for making semantic annotations to Web pages based on the information stored in the ontology.
From the point of view of the end user, a multimodal navigator is provided which also makes use of the ontology for
its configuration and interpretation of Web pages. This navigator incorporates a speech synthesizer, voice recognition
software, a haptic (tactile) mouse, an accessibility evaluator and an e-mail management system.
Keywords: Libre Software, Multimodality, Ontology,
Semantic Web, Visually Impaired People, Web Accessibility.
1 Introduction
Web accessibility can be defined as the fact that anyone
using any kind of Web browsing technology must be able to
visit any site and get a full and complete understanding of
the information contained there, as well as have the full
and complete ability to interact with the site [1].
Accessibility can be analysed from different points of
view, such as normative, legislative and technological. From
a legislative viewpoint, the USA led the way in 1998 with a
law that requires public sites to be accessible. Europe is
now gradually adapting its legislation.
The legislative context is essential but insufficient. It is
necessary to rely on normative guidelines that help us to
overcome existing obstacles. There are three main barriers
for the visually impaired user: hardware, software and the
information itself [2]. In this sense, various guidelines exist
on designing accessible hardware, browsers and content.
The Web Content Accessibility Guidelines, WCAG , specify in detail how to
make information accessible.
From the technological point of view, there are several
tools; some of these are intended for users and others for
designers; some are aimed at overcoming hardware barriers
and others are designed to overcome software or content
barriers. This technological disparity, variety of manufacturers
and lack of an integrated tool hinders real accessibility.
It was precisely this situation that led to the creation
of SAW, a System for Accessibility to the Web that takes
into account the end user as well as the designer. SAW com-
1 This work has been carried out under projects TIN2005-
09405-C02-02, 3PR05A016, PDT006A042 and
PDT006A045.
bines different tools in order to overcome the three main
barriers to accessibility: hardware, browser and content.
2 The SAW Project
SAW 1 , System of Accessibility to the Web, is an ontology-based
group of software components that aim to make
the Web accessible. The system also incorporates a special
mouse that allows blind users to surf the net. The relationships
between these elements are shown in Figure 1.
The ontoSAW ontology represents the attributes and re-
Authors
Fernando Sánchez-Figueroa has a PhD in Computer Science.
He is currently Vicerector of the University of Extremadura (Spain).
He is involved in several projects related to Web accessibility for
visually impaired people using mobile devices. He holds the Telefónica
grant for the "Application of Information and
Communication Technologies to the University Environment".
.
Adolfo Lozano-Tello is a teaching/research assistant professor of
Computer Science at the University of Extremadura, Spain. He
has a PhD (2002) in Computer Science. The subject of his PhD is
the use of software components and ontologies in applications.
His research interests include ontology engineering and the
Semantic Web. He is currently Director of the International Center
of Reference in LINUX systems in Extremadura (Spain).
.
Julia González-Rodríguez is a teaching/research assistant
professor of Computer Science at the University of Extremadura,
Spain. She is developing her PhD in Web accessibility
measurement. .
Mercedes Macías-García is a teaching/research assistant
professor of Computer Science at the University of Extremadura,
Spain. Her PhD subject is Web accessibility, which she has
examined in the context of SAW. .
UPGRADE Vol. VIII, No. 2, April 2007 67