PhD Thesis: Annotation and Transformation of Web Pages to Improve Mobility for Visually Impaired Users

The University of Manchester
Manchester, United Kingdom
2005

Web Site
In the last decade, the growth and the popularity of the World Wide Web (Web) have been phenomenal. Originally, it was a purely text-based system that allowed assistive technologies to be designed to transform pages into alternative forms (e.g., audio) for disabled people. This meant that for the first time, a vast amount of information was available and easily accessible to disabled people. However, advances in technologies and changes in the main authoring language, transformed the Web into a true visual communication medium. These changes eventually made the Web inaccessible to visually impaired users. In particular, travelling around the Web became a complicated task, since the richness of visual navigational objects presented to their sighted counterparts are neither appropriate nor accessible to visually impaired users.

This thesis investigates principles and derived techniques to enhance the travel experience for visually impaired Web users. The hypothesis is that travel support for visually impaired users can be improved if Web pages are analysed to identify the objects that support travel and are then transformed in such a way that they can then fulfill their intended or implicit roles. This hypothesis is supported by the identification of structural and navigational properties of Web pages which have been encapsulated into an ontology (WAfA) to support machine processing; and the design of a flexible pipeline approach to annotate and transform Web pages by using this ontology. An experimental test-bed, Dante, has also been created based on this pipeline approach, that encodes these principles and techniques to transform Web pages. Finally, a user evaluation method is devised and applied to demonstrate that the travel experience of visually disabled users can be improved through the application of these techniques.

This research demonstrates that by providing machine processable data, regarding the structural and navigational properties of Web pages, applications can be created to present Web pages in alternative forms and so enhance the travel experience of visually impaired users. The work presented in this thesis is of practical value to the Web accessibility community and is an important case study for demonstrating Semantic Web technologies. By moving away from thinking that simple translation of text to audio is enough to provide access to Web pages, this thesis is part of the coming of age of assistive technology and is a significant contribution to redressing the inequality arising from visual dominance in the Web.