Visualization By People Without Vision

Prototypes of two direct audio/tactile access methods are demonstrated that allow people with print disabilities to "see" diagrams, maps, charts, and other graphically-displayed information. All methods require that labels or other identifying information be available for each important object in a figure. In web applications, this additional information is accessed by exercising a link associated with an object. People with severe visual disabilities may need a tactile image mounted on a touch screen to access object-related information. It is expected that recently-introduced force feedback "haptic mice" may soon provide easy haptic access to the objects as well. The critical factor that ensures accessibility is availability of information about all important objects, since there is currently no way to transform any but the simplest purely visual graphic information into audio or tactile/haptic information that is easily understandable. These requirements, which also ensure good searchability, should influence development of future data structures and visualization displays. Introduction The mission of the Science Access Project (SAP) is to develop technologies that permit non-visual access to more complex electronic information. Until recently this research has concentrated largely on access to tables, math equations and other character-based information. Access is possible if this information is presented in some good mark-up language such as SGML and difficult to impossible when presented as bit-mapped images or visually-formatted text. More recently the SAP has begun exploring possible methods that permit good non-visual access to information conventionally presented as graphics. 1 Methods for Non-Visual Access to Graphical Information There are a number of audio technologies that are useful as substitutes or enhancements for visual presentation of graphical information. Many of these technologies rely on feedback from the computer to identify and display information about the important objects in the figure. Blind people have good access to many computer applications through use of screen reader software and either a speech synthesizer or a braille display. Speech technologies have proven to be useful to many people who are not blind. Many people suffer from visual dyslexia sufficiently that they can understand virtually nothing in prrint even though they may have perfect vision. It is also well understood that a substantial fraction of people are "audio learners" who understand what they hear better than what they see. All these people benefit from availability of speech and other audio output instead of or in addition to the normal visual display. However speech or other alternate access is presently limited largely to unformatted text. It is found, for example, 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. (Jacobson, in press). This "map-reading" method requires two things: 1. The computer must have some means of disclosing to the viewer the objects at any given location, and 2. the blind person must be capable of assimilating a spatial image of where various objects lie on this map. A common technique used to make assimilation of the figure easier is through use of a tactile image. Unfortunately there are no technologies for displaying refreshable tactile images on-line,