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This section will look more closely at each of the major components of electronic textbooks presented earlier and discuss the implications of making each of these accessible.
There are four basic ways in which text is presented visually in electronic textbooks:
1. Standard Text Draw. The electronic textbook uses the standard text writing routines of the computer and its operating system to draw text to the screen.
2. Proprietary Text Draw. The electronic textbook uses a text drawing method which is copyrighted by a single company and is available for use only by purchasing the software from that company.
3. Bit-Mapped Image. The electronic textbook is copied to the screen as an image.
4. Animated Text. The text is presented as a moving object or scrolled like a marquee. Either standard or proprietary text drawing may be used to accomplish this.
The text may also be presented by speech.
If built-in access is provided, none of the four above-named strategies for writing text to the screen presents a problem. With built-in accessibility, the same program which writes the text to the screen would provide the information in auditory form. The program can provide a parallel presentation of the information in alternate form; such as, speech.
Built-in accessibility should also allow the individual to move about in the text by section, paragraph, sentence, and word, as well as allowing the words to be spelled.
Presentation of information in auditory form is usually appropriate for individuals who are blind or have low vision but who do not have any hearing impairment. For individuals with hearing impairments or deafness, however, this form of presentation is a problem, unless the information is also available in visual form. For individuals with visual and hearing impairments, the information would need to be available in electronic form so that it could be presented using dynamic braille displays, as described above.
Electronic textbooks, which use standard text drawing, are compatible with standard screen reading software. Care must be taken, however, to ensure that the information is written to the screen in such a way that the individual can make sense of it using a screen reader which typically scans horizontally across the screen. Simple text layout on the screen can be very helpful here; side by side paragraphs would not work.
Electronic textbooks which use proprietary text drawing, bit-mapped imaging, or animated text are not compatible with today's screen readers. Electronic textbooks which use these strategies must use either built-in accessibility methods or incorporate advanced object-oriented strategies which would make the text version of the information available to the screen reading software. It should be noted that some software packages use display techniques, standard text drawing, proprietary text drawing and bit-mapped imaging all intermixed when writing information to the screen. One such software package reads Postscript Data Files (PDF). PostScript is a popular computer language used to drive office printers and many graphics programs use PostScript. If the fonts are resident (i.e., ready and waiting), it will use the standard routines discussed above. If the fonts are not resident, it will use its proprietary screen drawing routines to simulate the appearance of the font. At yet other times, text from this software package may be drawn to the screen as part of a bit-mapped image. This results in accessibility to only part of the text and this is not acceptable.
With regard to screen enlargement software, all of the first three methods of writing text to the screen would be compatible. Care must be taken, however, in how the information is laid out or dynamically changed to ensure that it is comprehensible to someone who is only able to view a small portion of the screen at any point in time.
A useful quick analogy is to think about trying to operate the electronic textbook while looking at the screen through a soda straw (to simulate the portion of the screen available to a screen reader) or through a paper towel core (to simulate a screen magnifier), especially when dealing with spatially laid out text or material.
In addition to providing access to the information from within the electronic textbook, it is sometimes possible for publishers to provide techniques for extracting information and presenting it as separate or companion text files. This text file could then be used in conjunction with a word processor and screen reader or voice output text file reader.
An external representation of the text in an electronic textbook could be achieved in two ways:
1. From the publisher. The publisher of the electronic textbook could provide an alternate form of the electronic textbook as an ASCII (American Standard Code for Information Interchange) or other accessible text file.
2. Extraction. A special tool could be provided by the publisher of the electronic textbook or a third party that would allow users to extract the information from the electronic textbook and store it as an ASCII or other accessible text file.
This approach is a viable approach for simple, static electronic textbooks which are composed primarily of text and which have stored in the electronic textbook a text version of any graphically or auditorially presented information. When such an extraction tool is used, it is important that all of the information which is conveyed in layout and formatting (e.g., bold, italic, and titles) be preserved, along with navigational aids (table of contents, indices, page references, and hyperlinks).
This strategy does not work for documents which have information presented in graphic or auditory form where an alternate text version of the information is not embedded in the document.
Additionally, this strategy works only for documents which are linear in nature (e.g., like a book or novel). For example, it does not work on material where the user can take any one of a large number of paths through the material.
Moreover, this strategy also does not work for materials which are in any way interactive.
Access to text formatting and hierarchy is important because it provides information about the structure of the information and to additional layers of information such as emphasis and key words. Text formats identify relationships between one text element and another (as in a definition), highlight key words, identify a sequence of presentation (as in a table of contents or headings in a chapter), provide information about the hierarchy of information (as with paragraph indentation) and provide other secondary levels of information to the reader. Making information about text formatting and text hierarchy available can be done in several ways, including:
Of these approaches, only the verbal tag approach would work with information which is exported to a dynamic braille display. For spoken output, the other approaches may be less disruptive, but will become more effective as techniques which relate specific auditory cues to specific text formatting features are developed.
As discussed under Text, systems with built-in accessibility have the advantage in that they are aware of any special formatting which is built into the text being presented and can take measures to present this information. Systems which are relying on external assistive technologies for providing access to the formatting information must use the standard system tools for formatting text so that they will be compatible with the screen readers. Some types of formatting and text hierarchy, however, may be difficult to present in a fashion that screen readers would be able to use or recognize and convey.
Graphic information within electronic textbooks falls into three general categories:
1. Information which is purely decorative and does not convey any particular information.
2. Information which is presented graphically but which is also presented in text form.
3. Information which is presented only in graphic form.
The challenges in making electronic textbook graphics accessible are:
1. Differentiating between important and decorative information.
2. Indicating the presence of information presented graphically.
3. Where appropriate, providing descriptions of the graphic images.
4. Where appropriate, providing alternate presentation of any important information which is presented graphically via description, tactile, or other appropriate means.
Text descriptions of graphic information may be either presented in parallel with the graphics for all users to see, or hidden in such a manner that it can be called up on request. Increasingly, accessibility researchers are finding that when information is hidden and available to be called up on request, it is requested by many users who are not blind. This feature adds to the comprehension of the graphic information by individuals with perfect vision.
There is great value in the redundant presentation (i.e., the repetitive display of the information in multiple formats, such as audio, closed captioning, descriptive video, braille and enlarged type) of information. For individuals who are blind or have visual impairments, it is often desirable to have supplemental methods or materials available in addition to any verbal descriptions to help in the presentation and interpretation of graphic information. Tactile models, raised line drawings, braille and audio tracks help provide orientation and information that enhance comprehension of graphic images.
In order to move about effectively within an electronic textbook, students must be able to independently and efficiently operate and navigate the textbook. Electronic textbooks use many methods to convey the structure of the content, such as simple outlines, expanding outlines, tab folders, and image maps. Electronic textbooks also draw upon a variety of methods to allow users to navigate the contents. These include menus, sub-menus, buttons, tab folders, outlines, scroll bars, icons, graphics, hyperlinks, and search functions. It is important for the student who is blind or visually impaired to understand what is contained within the textbook, how the textbook is organized, and what navigation options are available.
In general, these navigation methods can be made accessible to individuals with visual impairments. Some methods for achieving this include:
There is nothing inherently inaccessible about hyperlinks. The two major problems faced are (a) identifying when something is a link, and (b) having some idea of the context when one gets to the other end of the hyperjump. Hyperlinks are generally indicated through text formatting (e.g., the text is a different color or the text is underlined or italicized). If all of the formatting information is available to the user, the existence and location of hyperlinks is generally available as well. When an individual has executed a hyperlink jump, some type of a verbal announcement that a jump has taken place is useful as a cue to the individual that the "world around their soda straw view" has changed, so that they look around and reorient themselves to the place to which they have jumped.
In some cases, expand and collapse features may already be accessible. Problems arise, however, depending on how they are implemented in a given system. All expand and collapse features should be executable from the keyboard with speech or electronic text. All non-text visual cues that are provided in conjunction with the expand and collapse features should be available via built-in accessibility or revealed to the screen reader.
A subset of the expand and collapse feature would be a zoom feature. Such a feature allows individuals who are sighted to get a bird's-eye view of the general layout of the document or landscape. They can then zoom in for detail. The equivalent for those who cannot see would be the ability to provide an image which they could feel tactually. In addition, auditory cues could be provided to indicate white space, text and numbers. This would allow them to get a sense for the global layout of the page in the same way as a sighted individual.
In addition to the ability to search for words or phrases, it is also very useful to search for character formatting or for structural items in the document. For example, the ability to search for the next title is very helpful for stepping through a document. If structure information is not available, the ability to search for the next bold or underlined text can be useful.
As with graphics, audio information in an electronic textbook can convey important information, or it can be purely supplemental or decorative. For individuals who have visual impairments and perfect hearing, presentation of audio information presents no barriers. If the individual has a visual and hearing impairment, then any information which is presented auditorially would need to be available in amplified form or, if they had severe hearing impairments or deafness, in electronic form so that it could be presented via braille. The pace at which the auditory information is presented should be controllable to allow for different levels of comprehension. For example, it should be possible to speedup, slowdown, terminate, pause or replay speech.
Electronic textbooks may contain full-motion video in color or black and white, with or without sound. The audio portions of the movies would be accessible to students who have low vision or blindness; however, the students may have limited or no information regarding the visual information which is displayed on the screen. In order to make animation and movies accessible, the electronic textbook should provide:
For some electronic textbooks, it may be helpful to include supplemental materials such as tactile models, raised line drawings, braille or audio material which can provide orientation and information which would assist students who are blind or visually impaired to understand the graphic information or auditory descriptions.
This is one of the more difficult areas. Often, simulations where the user can manipulate the components rely on eye-hand coordination. An example of this is the model four-stroke engine described earlier in this document. In that example, the user could use a touchscreen or a mouse to grab the flywheel and turn it left and right in order to see how the pistons operate. Two strategies that can be used to make these systems accessible are:
1. Allowing all of the manipulations on the screen to be accomplished from the keyboard. This would also be useful for individuals with physical disabilities.
2. Providing auditory cueing of the status or change in status of the various components. Such auditory enhancement of the visual picture is usually beneficial to students with low vision as well as all students, including those without disabilities.
Caution must be used when designing modifications of interactive animation and simulations to ensure that the result does in fact provide the same quality of information to the student who is blind as it does to other students. In the example of the piston engine, the purpose of the program was to teach a child a specific concept. Even with the adaptations, the student who is blind would not have sufficient access to the information on the screen to learn that concept.
Other programs could be modified successfully. For example, a program might provide an animated story which periodically stops until the child responds to specific directions or answers questions by using the mouse or touchscreen. If there were a verbal (sound or tactual) narration of the story, and the student responses could be provided through the keyboard, then the child who is blind would have adequate accessibility to the content and could achieve the same results as other students.
Another opportunity for successful adaptation is the example where simulations allow students to carry out chemistry experiments. The beakers, flasks, burners, and other apparatuses are manipulated on screen and the chemical reactions (e.g., color changes, heating, and explosions) occur on screen as they would if the real items had been manipulated. If the interaction of the chemistry equipment can be manipulated through the keyboard, and the results of the manipulations are manifested by appropriate sound and descriptive narrative, the student would have information similar to that which is available in the chemistry lab.
Video conferencing is again inherently no less accessible than face-to-face communication. It is up to the individual communicating with the individual who is blind or who has low vision to make sure that information is not presented visually as a part of their interaction.
Where white boards or shared areas of the screen are used for drawing, writing, or otherwise working together, it is important that the white board area be implemented in such a way that it has either built-in voicing or works in conjunction with the screen reader for textual information. It should also be possible to print out the contents of the white board so that it could be converted into a raised line drawing using special adaptive equipment.
Controls for the video conference should be completely operable without vision. Providing keyboard access to all of the video conferencing controls is the easiest and most reliable way to achieve this.
Virtual reality environments can be divided into two general categories as follows:
The first is where the individual is experiencing a visual immersion. One example is a virtual reality environment that is used to allow an individual to walk through an art gallery. The second is the use of virtual reality as a metaphor for something which is not inherently visual. For example, there are a number of virtual reality tools being used to navigate databases and knowledge bases.
In the first case, the virtual reality simply represents another way of presenting information to which the individual who is blind did not previously have access. By making it electronic, it is possible that some additional access may be provided through the use of techniques and technologies for image enhancement and edge identification. These could be used in conjunction with tactile printers (e.g., braille printers) and raised-line drawings.
In the second case, it is important for any visualization tools which are created to navigate around in information space to be constructed in such a way that the nonvisual (e.g., verbal/textual) interface is preserved for those individuals who cannot use the visualization interface.
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