Non-visual access to the World Wide Web : investigations of design guidelines and haptic interfaces
This thesis investigates two different approaches to improving access to the Web for visually impaired people: the design of Web content; and the presentation of content. The potential for improving the design of Web content was investigated in an evaluation of the usability of the Web Content Accessibility Guidelines of the Web Accessibility Initiative. Student Web page authors used the Guidelines to adapt Web pages containing various elements (such as images and tables). These pages were collated into a Web site, which was evaluated by visually impaired people. The page authors found it difficult to find the information they required in the Guidelines document, and had difficulties with implementing the advice of the guidelines. The visually impaired people who evaluated the pages found that the extent of the accessibility of the different elements varied depending on the individual’s experience of using the Web, and the software they used. The accessibility of some elements was not improved by the implementation of the guidelines. The potential for improving the presentation of Web content was investigated using a haptic device. The perception of virtual textures and objects by blind and sighted people via this device was examined. It was found that the virtual textures were perceived differently to the real textures examined in the literature, and that the blind people could better discriminate between the textures than the sighted people could. The virtual objects were explored from the inside and from the outside. It was found that objects generally felt larger from the inside than from the outside. This has been termed the ‘Tardis’ effect. The thesis concludes that it is difficult to define what we mean by ‘accessibility’. Without a clear definition it is not possible to judge whether a Web site is ‘truly’ accessible. The difficulties in making Web content fully accessible mean that additional methods are required for presenting the content in different ways. The researcher believes that haptic devices offer one such method, and could be particularly useful in presenting information that is visual in nature, such as information laid out in columns.