Computer access
- Text and graphics enlargement on computer screens
- Split Screen Display
- Synthetic Speech Output
- Electronic Braille Output
- Screen-reading software
Text and graphics enlargement on computer screens
Description
While software options are discussed below, the most simple method of producing a larger image is to use a larger monitor. This is especially effective for people who require only minimal magnification. Unlike software options, a large monitor alone does not distort the original layout.
There is now quite a wide variety of software and software/hardware systems available which provide enlarged text on computer screens. Most of these packages have been specifically developed for use by people with impaired vision.
Facilities for adjusting print size in a range between normal and 16 times are common. It is also possible to adjust screen colours (both foreground and background) independently of other software which is running on the computer. There are many other sophisticated facilities for manipulating the screen display, given that the enlargement distorts the original layout. Some manufacturers also offer synthetic speech output in conjunction with text enlargement. This is especially valuable for people whose level of vision is marginal for reading or is deteriorating. Packages exist for both PC (MS Windows) and Apple Macintosh computers.
Advantages
In most cases, the installation of software alone provides large print on an otherwise standard computer. This allows a person with quite poor vision to read the screen while maintaining good posture. It also provides the person with ready access to virtually all commercially available software. Cost is generally quite modest.
Disadvantages
The user must undertake additional learning to utilise enlargement software. The original screen display is distorted. Some extra computer memory is required.
Split screen display
Description
Many CCTV models offer a split screen facility. It is possible either to switch between material on a page and that on the screen or to divide the screen between both sources so that both are present simultaneously. Importantly, the CCTV does not magnify the computer-generated material-that must be done from software on the computer
Advantages
The facility is valuable for doing such tasks as copy typing, entering data taken from paper forms or writing while reading from paper-based references. Hardware can be reduced by using one monitor for both CCTV and computer displays. The use of only one monitor can also provide a better ergonomic environment.
Disadvantages
The movement of the two text sources on the screen makes some people feel nauseous.
Synthetic speech output
Description
Developments in this field since the early 1980s arguably represent a more significant advance in access to information by people who are blind or severely visually impaired than any other. Text, provided it is on a computer, is or can be made accessible to blind people. A speech synthesiser can be hardware-based. In that case, it consists of a circuit board (or card) to be fitted into a standard computer or purpose-built device. Alternatively, there can be an external unit to be connected to the computer’s serial, parallel or USB port, depending on model.
In the second half of the 1990s, software-based synthesisers became available for MS Windows. This software uses the sound card in either a desktop or portable computer to produce high quality speech at substantially less cost than a comparable dedicated card or external device.
To allow a blind person to use a range of computer operating systems and applications, screen reading software is used. This software, in turn, can send information which is usually displayed on the screen to a speech synthesiser and/or an electronic Braille display. Alternatively, a software package specifically for use by blind users can be employed on a standard computer. Yet another option is a purpose-built note-taking device.
Items ranging from talking dictionaries to talking maps and satellite navigation systems are possible (if not broadly available) because of the availability of synthetic speech. Note that important facilities such as talking clocks and watches, thermometers, scales and calculators usually use digitised human speech. This is different to synthetic speech in that only a limited, but usually very well annunciated, vocabulary is available. Synthetic speech, on the other hand, can pronounce a wide range of words relatively well. The level of accuracy varies between examples. For that reason, most screen-reading software provides means by which the synthesiser can be ‘tricked’ into pronouncing a given word correctly.
Advantages
Synthetic speech allows standard computers to be adapted or specialised devices to be built for relatively low cost. While most synthesisers do not completely replicate human speech quality, following a quite short period of familiarisation many people can read information with a high degree of comfort and at high speed. This technology can make much information readily available to blind people, especially when combined with other new technologies (the same applies to electronic Braille display. These include optical character readers, CD-ROMs and Internet-based resources. Blind people can also competitively perform many computing tasks such as word processing, data entry and information retrieval, sending and receiving electronic mail, programming and so on.
Disadvantages
A period of familiarisation is often necessary before a new user can understand the speech comfortably and accurately. Some people find it difficult to concentrate for long periods when using speech output. Speech synthesisers are not useful to people who have both a severe vision and hearing loss. It can be more tedious to gain an accurate representation of spatial layout using synthetic speech than using electronic Braille. Examples are determining the amount of white space between words or paragraphs and being aware of indented text.
Electronic Braille output
Description
Conventionally produced Braille-that is on paper-represents a very bulky medium. Over the past two and a half decades a considerable number of paperless Braille systems have been developed. As with synthetic speech, electronic Braille displays can be connected to standard computers or incorporated into purpose-built devices.
Each Braille cell consists of a 2 x 3 or 2 x 4 matrix, so there can be up to eight dots in one cell. A row of cells consisting of plastic pins form the Braille characters in electronic Braille displays. Displays are generally between 18 and 80 cells. A common but not universal feature is cursor routing. A button behind each cell can be pressed to route the cursor to that position, which is extremely useful when editing.
Advantages
This technology can make much information readily available to blind people, especially when combined with other new technologies. These include optical character readers, CD-ROM and Internet-based resources. When used in conjunction with screen reading software, electronic Braille displays allow blind people to perform competitively many computing tasks such as word processing, data entry and information retrieval, sending and receiving electronic mail, programming, etc. Portable note taking devices can also employ these displays. Good Braille readers enjoy the linear display. Spelling and punctuation and to some extent layout are immediately available. This is in contrast to using synthetic speech output, where it may be necessary to interrogate the machine to get the information. Braille output can also be very helpful for retrieving information while performing a highly audible task such as talking on the telephone. Material can also be read in a group setting without the complication of earphones. For those blind people who also have a significant hearing loss, electronic Braille offers a great deal of potential, both vocationally and for personal communication.
Disadvantages
Cost remains quite high when compared to speech or large print. This is partly due to the intricacy of the equipment and partly to the low volume of people using Braille. Braille displays are usually somewhat bulkier and heavier than speech output. There is a higher potential for malfunctions than with speech or large print displays because the Braille pins are operated mechanically.
Screen-reading software
Description
This software is an intelligent link between a computer and a speech synthesiser and/or electronic Braille display. It endeavours to send relevant information to the output device. The extent to which this is achieved depends partly on the capacity of the particular screen reader and partly on the design of the operating system or application being used. There are screen readers for most operating systems including MS DOS, the various MS Windows versions, Apple Macintosh System 8.6, OS/2 and Linux. Screen readers can be configured to provide the user with more or less information through the speech synthesiser, depending on personal preference and the task being performed. Typically, there are also facilities for silencing portions of the screen (such as a clock or status line) and monitoring portions of the screen for changes. The screen reader, especially in GUI (graphical user interface) systems, must recognise and be able to alert the user to a wide range of visual distinctions. These include colour, font, attributes such as bolding, highlighting, dialog boxes and menus. In a GUI environment, screen readers should also provide the user with information about iconic symbols. This can require initial labelling of the graphics, sometimes involving sighted assistance. The user can instruct the screen reader, for example, to read as much as an entire document or as little as the current character. In a GUI environment, the mouse pointer is moved by pre-determined increments through keyboard commands. It is, however, often more effective to use shortcut keys than to emulate the mouse.
Advantages
As mentioned when discussing speech synthesisers and electronic Braille displays, people who have little or no vision can operate standard computers with a high degree of effectiveness. This includes gaining access to the Internet and to information sources such as CD-ROMs. That is, blind people can have independent access to a great deal of information for recreational, study and vocational purposes.
Disadvantages
To operate much current commercial software, a blind user must be able to conceptualise highly visual layouts. It is also necessary to learn sometimes complicated keyboard manoeuvres to issue commands to both the screen reading and commercial software.
