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© Novática Information Technologies for Visually Impaired People Figure 3: Editing Accessibility with EditSAW. special perceptual possibilities, such as linking each Web page element to a voice file or Braille file that describes the content or functionality of these elements. 4 EditSAW: Accessibility Editor for Web pages One contribution of the SAW project is the transformation of existing Web pages into accessible Web pages by using the software tool editSAW, which is based on the ontoSAW specifications. In order to do this, it adds semantic annotations [4] to the elements that appear on existing Web pages to be interpreted by naviSAW. EditSAW can be used not only to identify which elements of the Web page lack accessibility, but also to permit the designer to modify these elements to incorporate attributes that will make the page fully accessible. It provides added value by allowing the incorporation of other characteristics that improve the perception of these page elements by blind users (voice files, etc). Figure 4: MouseSAW and Close-up of its Pin Cells. Figure 2 shows an example of an element type Table, into which the attributes ontoSAW:resume, ontoSAW:rows, ontoSAW:columns, ontoSAW:Braille and ontoSAW:voice, with their corresponding values, have been incorporated. In order to make a Web page accessible, editSAW first connects to the ontology via the Internet. If the ontology has incorporated new elements and attributes according to the latest W3C or WAI recommendations, these new characteristics will therefore be considered dynamically by editSAW. After identifying the URL Web page that the designer wants to use, its content will be analysed and the elements which are not accessible will be displayed (in Figure 3, these are shown with a circled icon). The designer will be able to modify the attributes of these and other elements simply by selecting the appropriate icon and entering values for the corresponding attributes. Once no more circled icons remain (that is, all Web page elements have their attributes with appropriate values for accessibility), UPGRADE Vol. VIII, No. 2, April 2007 69
Information Technologies for Visually Impaired People Figure 5: a) Web Page of a Digital Newspaper in a Conventional Browser. b) The same Page in NaviSAW. the new accessible page can be saved. To sum up, editSAW modifies the HTML code of original Web pages, incorporating labels that make elements accessible and others that will help naviSAW to provide added accessibility options. These special annotations that editSAW carries out form perfectly valid pages. Standard browsers (Mozilla and Explorer) ignore these labels although they show all the other attributes of the elements in a conventional way. However, naviSAW will use these annotations to offer improved accessibility to impaired users, as described in Section 6. 5 The Braille Mouse: MouseSAW Visually impaired users have the ability to overlap different conceptual maps. mouseSAW uses this ability to manage the browser as well as the contents represented within it [5]. The mouse is shown in Figure 4. The main ideas have been extracted from the VTMouse [6]. It was originally designed for computer games, but has been configured and programmed in our laboratory to represent useful information in a haptic manner. This mouse behaves in the same way as a conventional mouse, but two cells of pins have been added. One of the cells informs the user which panel is currently active. The other one represents the element beneath the mouse pointer (a table, an image, etc). 6 The Multimodal Browser: NaviSAW NaviSAW is a multimodal browser that allows users to access Web pages using different modes: visual, auditory and tactile. All these modes are optional and compatible with each other. The browser assists in selective surfing based on the class of elements stored on a Web page, according to the previous classification made in ontoSAW. Figure 5 shows the normal appearance of a Web page in a conventional browser and the final result, after being transformed and displayed in naviSAW. Each element of the original page is defined with an icon on the transformed page. Take the Web page logo, for example. Originally, it was positioned in the top left hand corner. This element is classified as an “image” and transformed into a specific icon. It maintains its original position, the top left hand corner, on the transformed page. Another example is the page menu, a list of links. This menu has been transformed into a “list”. In this case, the element contains other elements, the links. We can access these items using the “expand” action defined for this type of element in ontoSAW. The naviSAW interface is divided into four panels, with movement being restricted within each panel. If the user wants to change the active panel, he has to use a combination of keys or, alternatively, a voice command if the speech synthesizer has been activated. Each panel has different functionality; some of the panels are explained below: Navigation panel. This contains the URL, "back", "go to", "refresh", "stop" and "home" buttons, and also the browser add-ons, such as the speech synthesizer, voice recognition software and mailSAW, which is used for reading mail. Selective navigation panel (on the left of the screen). This contains a button for each type of Web page element. The element types are defined in the ontoSAW ontology. When one of the buttons is pressed, a filter is activated over the content of the page displayed. Visualization panel (in the centre of the screen). The Web page is represented in this panel. Each element of the original Web page is represented as an icon. This icon stores its position on the page in terms of rows and columns. mouseSAW can surf through these elements, obtaining haptic information from them. When the mouse pointer is positioned over an element, a contextual menu appears. This menu, called the “accessibility menu”, could be read out by the speech synthesizer. Its content is dynamically obtained 70 UPGRADE Vol. VIII, No. 2, April 2007 © Novática
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