CD-ROM Access
Solutions
Choosing appropriate solutions
Access to Graphical User Interfaces (GUIs)
Access to tables
Access to multimedia and images
Access to math equations
Access to graphs
Choosing appropriate solutions
Software accessibility solutions fall into two categories of access -- direct and indirect, defined below. To determine the most appropriate access a product can provide, several factors must be considered -- target age group of a piece of software, technical constraints on the software's design, and the educational goals of the product. Our discussion here focuses on educational software rather than business software, so educational goals are particularly important.
A "directly accessible" product is designed so that a blind person can operate all on-screen controls and access the product content without relying on the aid of a screen reader or magnifier. Many vision teachers report that their younger students get limited training with assistive technologies. For this reason, built-in access is most crucial in products targeted for the elementary and middle school level. A directly accessible product should have a keyboard interface with audio output. Audio should announce the presence and status of all on-screen controls and convey the atmosphere of the software.
Providing direct access has benefits in many cases. The largest is that the user is able to access educational software without needing special assistive hardware and software. This keeps costs down for schools and reduces the amount of technical problems to be overcome. It also allows the blind student to sit at any computer rather than always being directed to the adapted workstation. Having students with disabilities be as flexible as other students promotes inclusiveness in the classroom. Finally, having the accessible interface designed by the people creating the software may create better interfaces since the designers understand the intent of each control better than an assistive technology may be able to interpret it.
An "indirectly accessible" piece of software is designed with a screen reader and magnifier in mind. This level of access assumes the user has a preferred assistive technology package installed and is relatively comfortable with it. Software that falls into this category is likely to be targeted at the high school level and beyond. An indirectly accessible product is designed with "hooks" to facilitate ease of use with a screen reader or magnifier. These hooks can be implemented by developers with tools like Microsoft Active Accessibility (MSAA) and the Java access API from Sun, which are discussed in more detail in the next section, access to GUIs. Exposing the system cursor and using standard controls and fonts can also help make a product indirectly accessible.
Indirect access can have some advantages. It may provide consistency of operation since the student already knows how to navigate with their screen reader or is continually gaining competency in doing so. In some cases it may be less expensive to develop the software this way and it could save disk space for a large application, both of which should appeal to software companies. Screen reader accessibility is also the easiest way to provide access to Braille users, since techniques for providing direct output to Braille displays are uncommon. An additional benefit of building software that is cooperative with screen readers is that it will probably work well with other assistive technologies including alternative input devices such as scanning utilities, on-screen keyboards, and voice recognition.
It is important to note that not every product can be made accessible. The educational goals of a program are sometimes incompatible with providing non-visual access, especially for students who are blind. For example, many programs for young children teach visual concepts, such as counting and color pattern matching. While blind students do need to learn to count and to make patterns, a program that uses only visual ways of teaching these skills is a poor candidate for adaptation. In their report "Accessibility of Information in Electronic Textbooks for Students Who are Blind or Visually Impaired," the Texas Education Agency gives an example of a simulation of a piston engine. This software might provide a keyboard interface for adjusting the engine and verbal descriptions and sounds to convey the motion of the parts of the engine, but it has no inherently non-visual information to provide and for that reason is not a good candidate for adaptation. A visually impaired student using that simulation might learn that "a flywheel is a left/right button," says the report, rather than learning how the parts of an engine fit together and how they work.
Low-vision students, however, may still learn from a visual program, provided it is well designed. Software should allow fonts to be adjusted, provide clear contrast for objects that students must locate and manipulate, include keyboard commands to reduce mouse dependence, and provide a system cursor that moves with important screen events so that magnifiers can track them. With these features in place software with a range of educational goals can benefit students with some useful vision.
Access to GUIs
Navigation through graphical user interfaces (GUIs) is difficult primarily because the buttons, menus, and other controls that the user must manipulate to move around and make choices are often invisible or nameless when viewed by a screen reader. In addition, the use of custom cursors rather than the true system cursor leads to trouble. One possible solution for software built for the Windows 95 platform is Microsoft Active Accessibility (MSAA), an applications programming interface (API) for exposing elements of the screen and their state, including exposing the focus of the screen. Using MSAA, software developers can use entirely graphical custom interfaces while still making each element known to the screen reader. Current versions of the most popular screen readers have been programmed to read this information and convey it to the user. MSAA has been implemented in some Microsoft products and in Lotus Notes R5.
The growing popularity of Java as a programming language for the Internet has led to the development of the Java Accessibility API. With some similarities to MSAA, Java Accessibility allows software developers to expose the location, names, and states of each control while still using the graphical look-and-feel of their choice. The Java Swing Set's pluggable look-and-feel holds out hope that each user could "plug in" the interface that suits them best, with visually impaired users choosing larger objects and fonts while blind users choose an audio-enabled interface or one that works well with their screen reader. The first broadly distributed way for blind users to access Java applications is the IBM Self-Voicing Kit. It provides tools that Java developers can add to their programs to create a screen-reader style of access using built-in code. Read about our Java prototype for more information. Screen reader companies are also developing the means to convey the Java accessibility information to users of their Windows-based screen readers.
Access to tables
Reading and manipulating tables is an important way of processing scientific information and is a particular problem for blind users. Using data in a table requires referring to the headings for the row and column in order to interpret the information in a single cell. When navigating the tables in most current software the blind user doesn't even know what cell they are in at any time, no less the column and row headers that apply. A standard method is needed for letting screen readers know which headers apply to each cell, such as that included as part of the HTML 4.0 specification from the World Wide Web Consortium (W3C). The Web Accessibility Initiative of the W3C is proposing standards for user agents (browsers and other end-user tools) to provide appropriate navagation through properly coded tables. Once these features are incorporated, screen readers can create appropriate navigation commands and respond with the data for each cell in context. This will permit blind users to explore a set of tabular data more efficiently.
Access to multimedia and images
Making math and science content accessible will require creative thinking as well as some work on underlying development systems. Adding description of still or moving images so that they can be better understood by blind or visually impaired students can be accomplished by providing recorded human audio or through use of text on the screen which can be read using synthesized speech. An additional audio track synchronized with the video's soundtrack is most effective for videos and animations, while a plain text solution might be adequate for still images, depending on the ages of the users.
NCAM's Web Access Project offers information on three formats which allow the addition of captions and audio description to digital multimedia. QuickTime from Apple was the first tool to provide these capabilities. Two newer specifications, under development at Microsoft and by the World Wide Web Consortium, respectively, are SAMI and SMIL. Both provide the means for placing additional audio, text, or visual objects in a multimedia presentation, offering a technique for captioning and describing multimedia for CD-ROM and Web products.
Access to math equations
Improving access to equations and graphs are crucial pieces of making math and science accessible to visually impaired students. Currently, software that presents equations may use any number of ways to display those equations, from a standard character set with an occasional graphic mixed in, to custom fonts, to putting each equation entirely in a graphic. None of these representations can be read by a screen reader, though most can be magnified adequately. Screen readers will not be able to support mainstream math software until that software exposes all equations in a standard way that screen readers can understand.
One existing standard is TeX, a typesetting standard used widely by mathematicians and scientists. Another NSF-funded project is looking at ways to use LaTeX (a version of TeX) to provide access to mathematical materials. MAVIS (Mathematics Accessible to Visually Impaired Students) has created tools for converting LaTeX to Nemeth code for easier production of Braille materials. They are now working on an audio screen reader for mathematics and a tool to translate Nemeth Code back into print mathematics.
A newer standard is MathML from the World Wide Web Consortium which includes the ability to mark-up math for either semantics (meaning) or presentation. We understand that major developers of mathematics tool software hope to use MathML to improve compatibility between their various math products. If so, this may become a very useful way to access math content with assistive technologies. Whatever means is found for exposing math equations fully, screen reader developers will then need to implement ways to interpret this information and verbalize it in a way that is useful to users. The MAVIS researchers plan to use MathML in their tools, which may provide one solution to these problems.
A company called Metroplex Voice Computing has developed speech recognition products to make it easier to enter math equations into documents. Users can learn voice commands to create complex equations and reduce the number of keystrokes needed. The products also include some text-to-speech capability for reading back the equations produced.
Access to graphs
Graphs present a slightly different problem. How can the content of a graph be conveyed to a blind user? One option is to print the graph in tactile form, and recent advances in creating graphical embossers and setting standards for tactile graphing make this more possible (see the Tiger Advantage from ViewPlus Technologies and the tactile graphs available from the TAEVIS Project). Another possibility is to present an overview of the graph in audio and allow exploration to find the numerical values of important points. We hope that continuing research on both practical methods of producing tactile graphs and innovative ways to present information through audio may lead to increased use of these techniques.
