Web Posted on: December 3, 1998

Accessing Object-Oriented Web Graphics

Introduction

It is now possible for virtually any person to read text in well-authored web documents. However there is a considerable amount of web information that still is not available in practice to people with print disabilities. For example, most math formulas and tabulated information is either very difficult or impossible to read using present access technologies.

The recent introduction of mathML and improvements in access technologies should eventually make it possible for people with print disabilities to access math and tabulated materials as well as plain text. However none of these developments can provide access to the great quantity of information currently presented in graphs, charts, diagrams, and other kinds of graphical representations. This is a particularly serious problem for students and professionals in science, math, and technology, because graphical information is often critical to understanding textbooks and publications in these fields.

The Oregon State University Science Access Project (SAP) has begun a series of projects intended to make it possible for authors of the future to present not just the pictures of information in electronic documents but also the original information from which those pictures are derived. That information could make possible good access by people with print disabilities. This paper discusses new developments for one important type of graphic presentation - the object-oriented representation.

The research is still far from complete, but some people, notably service providers for advanced students and professionals, may already find this a better and less time-consuming method for providing good access to a number of complex figures. One of the very great advantages to methods described here is that a figure can be made accessible for a broad population. A single labled web figure becomes accessible to people as diverse as braille- and non-braille reading blind people and people with severe visual dyslexia.

Current Techniques for Making Graphics Information Accessible

There are a number of audio technologies that are useful as substitutes or enhancements for visual presentation of maps, charts, diagrams, and other types of object-oriented graphical information. Many of these technologies rely on feedback from the computer to identify and display information about the important objects in the figure.

For example, [Jacobson and Kitchin] reported that blind people can "read" maps rather well by using a touch screen and running their fingers along a road or railroad track, interrogating cross streets as they are encountered, etc. This "map-reading" method requires not only a touch screen but also graphics software that can provide information to the viewer about any major object on the screen. In this case the names of streets, railroads, foot- and bike-paths, etc.

This access method relies on the user's ability to assimilate a mental spatial image of the map. A tactile image reduces the mental effort, and this combination of touch and audio(or braille) feedback has been found to be very successful in making maps and other graphics accessible to blind users. See [Parkes] reference.

Unfortunately, there are no technologies for displaying refreshable tactile images on-line, but it has recently become possible to create a tactile copy of a computer picture. This figure on a touch screen or other digitizing tablet permits a blind user to feel the tactile images, and receive audio feedback from the computer about those images. The [TIGER printer] is very convenient for this purpose, but people who have no TIGER can use [swell paper] to make tactile copies.

Off-line printing is time-consuming and makes it very difficult for a blind person to take advantage of features like zoom views. A number of on-line haptic technologies are being developed. The purpose of these devices is for use with virtual reality. One such technology, the haptic mouse, has already been introduced or announced for imminent release by several companies including Immersion Corporation (San Jose, CA, USA) and Control Advancements (Kitchener, Ontario, Canada). These devices may soon permit blind people to explore graphics on-line.

Adding Information to Existing Web Graphics Formats

The critical necessity for any of these methods to work is a well-structured data format that includes labels and other information about objects and the location of these objects in the figure.

The SAP is developing methods for permitting this kind of information to be added and displayed for bit map graphics on the world wide web. These labeled graphic files are accessible, in principle, to users with print disabilities.

One access method that is simple but often sufficient for people with low vision or dyslexia and in many cases for people who are totally blind requires a touch screen or other digitizing tablet that acts as a mouse. The user can move around this pad and hear names spoken as the pointer crosses into objects. Better access for blind users is achieved if a tactile picture is placed on that digitizing pad. Future expansion of the plug-in used for enhanced access can, in principle, use audio for object location and make use of new hardware developments such as haptic mice.

The authoring tool permits an author or editor to add labels to an existing graphics image. The graphics file is called by the program, and the editor then indicates each important object in the picture and gives it a label. The program generates an accessible "information page" that can be provided to students or that can be easily called by an "information link" associated with the original web graphic. A service provider can make a tactile copy of the figure for blind clients with little or no editing. The current state of this research program will be discussed, and a number of examples of accessible maps and scientific diagrams will be shown.

Acknowledgements

This research was supported in part by the National Science Foundation.

References

Jacobson and R. Kitchin, "Geographical information systems and people with visual impairments or blindness: Exploring the potential for education, orientation and navigation" Transactions in Geographical Information Systems 1998 (in press)

Parkes "NOMAD": AN AUDIO-TACTILE TOOL FOR THE ACQUISITION, USE AND MANAGEMENT OF SPATIALLY DISTRIBUTED INFORMATION BY PARTIALLY SIGHTED AND BLIND PERSONS" Editors. A. F. Tatham and A. G. Dodds Proceedings of the Second International Symposium on Maps and Graphics for Visually Handicapped People King's College, University of London, April 20-22 1988, pp. 24-29

[TIGER printer] The TIGER TactIle Graphics EmbosseR was developed by the SAP and is commercially available from ViewPlus Technologies, Inc., 3223 NW McKinley Drive, Corvallis, OR 97330, http://www.viewplustech.com

[swell paper] is a special paper that can be used to make tactile copies by radiant heating that causes black areas to swell. http://www.repro-tronics.com