2000 Conference Proceedings

Go to previous article 
Go to next article 
Return to 2000 Table of Contents


USING MICROSOFT ACTIVE ACCESSIBILITY IN A WEB BROWSER FOR THE BLIND AND VISUALLY IMPAIRED

M. Zajicek and I. Venetsanopoulis The Speech Project, School of Computing & Mathematical Sciences, Oxford Brookes University, Headington Oxford OX3 0BP

1. Introduction

This paper will be of interest to those seeking to integrate rehabilitation software with mainstream Microsoft products. It reports the results of one of the Microsoft Accessibility Product Development Awards announced at CSUN 1998, the BrookesTalk Adaptation Kit Project (BAK)

Researchers at the Speech Project at Oxford Brookes University, have developed a World Wide Web browser for the blind and visually impaired called BrookesTalk. Further details can be found at http://www.brookes.ac.uk/speech. BrookesTalk enables users to move quickly about the Web by providing functions that mimic sighted users’ visual scanning of the Web. Page summarisation is the most powerful of these functions providing an extracted abstract about 20% the size of the page.

The aim of the BAK project is to integrate BrookesTalk special features for easy World Wide Web browsing with Internet Explorer using Microsoft Active Accessibility http://www.microsoft.com/enable/msaa/?RLD=185. This provides plug-ins (APIs) to Microsoft software to enable integration with adaptive products http://msdn.microsoft.com/workshop/ .

The completed system will significantly increase the number of different Web browsing functions available to blind and visually impaired users. It will have full Internet Explorer functionality integrated with BrookesTalk easy web browsing.

Interface design for BrookesExplorer provides a particular challenge. The rich functionality of Internet Explorer together with the BrookesTalk easy access functions demand ingenuity in their presentation at the interface for blind users using keyboard only.

2. BrookesTalk easy Web searching features

The easy Web search features of BrookesTalk which have been modularised and integrated with Internet Explorer are described below

2.1 Saving search results

BrookesTalk creates a list of real search results on a search engine results page as distinguished from links put on a search Engine results page for commercial reasons. BrookesTalk separates out the results of the search and provides a concise list containing only the search results. The list is resident in the system until another search is performed and is easy to return to even if the user has already started to follow search result links. This facility was particularly appreciated by blind and visually impaired users who often get lost on a search results page.

2.2 Page summary

BrookesTalk provides a page summary consisting of the number of words, headings, links, images and keywords found on a page (Zajicek et al, 1998a). This function enables blind and visually impaired people to know what type of page they are visiting thus enabling them to infer the structure of the site. For example if the first few pages of the site contain few words and many links then we can infer a hierarchical tree structure.

2.3 Keyword list

BrookesTalk provides an extracted keyword list for the page (Zajicek et all, 1998b) which can be used alongside the meta keywords provided by the author to judge the contents of a page. With experience, the juxtaposition of extracted keywords based on the text of the page, and meta keywords based on the author’s concepts of the page, can provide useful insights into page content.

2.4 Extracted abstract

BrookesTalk provides a scanning action in the form of an abstract which is a collection of significant sentences drawn from the page. Using a combination of information retrieval techniques and natural language processing, we have extracted the key tri-grams (phrases consisting of three words) from the contents of the page. We then put them back into the sentences in which they were found and present the collection of sentences as the abstract of the page. Abstracts usually contain about 25% of the number of words of the whole page. This cuts down the reading time of the page using synthesised speech. The abstract consists of a set of disjoint sentences. The semantics of the sentences are preserved, unlike keywords, and the listener can make a good guess as to the content of the text left out between the sentences. In this way users can find where the required information lies on the page to be read out in detail later. Keywords and abstracted sentences represent the words and sentences picked out when a sighted user scans a Web page.

3. Integrating BrookesTalk with Internet Explorer

BrookesTalk is a stand alone Web browser for the blind and visually impaired which does not rely on any other software for Web access. The aim of the project is to ‘wrap’ BrookesTalk around Internet Explorer to form the new expanded application, BrookesExplorer . This means that the user has full access to the graphical interface of Internet Explorer and the function key driven interface of BrookesTalk with its special fast web access features. The prototype interface presents the BrookesTalk control bar at the right hand end of the Internet Explorer menu bar for sighted users.

BrookesTalk is written in the Object Oriented language Visual C++. When we come to integrate BrookesTalk with Internet Explorer we can isolate the code for fast web access algorithms, search results retrieval, page summarisation, keyword extraction and abstracting, as modules or objects. These are then attached to Internet Explorer through the events available through Internet Explorer.

The BrookesTalk control bar or interface is a visual object attached to Internet Explorer using Javascript and the interfaces provided by Internet Explorer.

4. Interface Design Challenges

4.1 Use of BrookesTalk features

A prime concern is the presentation of the functionality of the system to blind and visually impaired users. At the Speech Project we have already performed an evaluation exercise, with over 200 users, using function key driven BrookesTalk (Zajicek et al, 1999). We looked especially at which of the easy Web search functions were most useful and the strategies employed by users as they moved around the Web searching for information.

It was found that our subject users fell into two significantly different groups, (i) those who were Web literate and had used Web browsers for the blind before, and (ii) newly blind users who were often elderly who had little previous experience of computing or the Web.

The most useful results concerning use of BrookesTalk facilities, were obtained from group (i). In this group the search, summarisation and abstracting facilities were the most frequently used. A standard pattern emerged for most users whereby they used the summarisation facility to move through a site following links and working out what type of page they were on. When they found an information rich page, usually with a large amount of text and few links they used the abstracting facility to find where the information lay. If they didn’t find the information in the abstract they then read out the whole page in document mode.

Group (ii) provided valuable insights into the problems faced by the non computer literate in using software for the blind and visually impaired. They were often frustrated with their experience. They encountered difficulties mainly because they had no clear idea of the way the Web works. 65% of this group were unable to work successfully with the Web.

4.2 How to represent complex functionality using keyboard only

Elderly visually impaired users experienced significant problems getting to grips with the BrookesTalk control bar where each function had its own function key. Increasing functionality, in BrookesExplorer, means that functions have to be organised in a form of hierarchical menu system which must be conceptually relevant to the user. If users cannot understand the relevance of groupings they will have to search for each function separately without any point of reference.

We will demonstrate the functional hierarchies that proved to be the most successful for BrookesExplorer and report on the results of our evaluation exercise.

The work is ongoing. The completed system will be ready for demonstration with this paper at CSUN.

References

Zajicek M., Powell C. and Reeves C. 1998a, ‘A Web Navigation Tool for the Blind’ Proc. 3rd ACM/SIGAPH on Assistive Technologies, California

Zajicek M., Powell C., Reeves C., Griffiths J., 1998b, ‘Web browsing for the visually impaired’, IFIP/ICCHP’98 6th Int. Conf. on Computers Helping People With Special Needs, Vienna Budapest

Zajicek M., Powell C., Reeves C., 1999, ‘Evaluation of a World Wide Web scanning interface for blind and visually impaired users’, Proc. HCI International 1999


Go to previous article 
Go to next article 
Return to 2000 Table of Contents 
Return to Table of Proceedings


Reprinted with author(s) permission. Author(s) retain copyright.