For Persons with Disabilities
›
Introduction
›
Disabilities Affecting Computer Accessibility
›
Computer Accessibility Strategies
›
Computers are used by a wide range of different people, and majority
of those people can use computer without any problems, but there are
some people in the work places which have various needs which make
using computers difficult for them.
›
The speed of living is becoming quicker in our society, the society
demands quicker reaction and feedback from every one even from
persons with certain disabilities.
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Worldwide, at least one person out of ten is disabled due to physical,
mental or sensory impairments
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Developments in HCI are now allowing people with different
disabilities such as visual or hearing impairments to use a computer
and to communicate with each other without a problem.
›
There are several types of disabilities that can affect computer
accessibility. An indicative list of impairments includes the
following:
▪
Visual impairments:
• Blindness, low vision and color blindness.
• Includes blind people rely on hearing and touch to use computers. • A person can be completely blind, color blind or low vision.
▪
Motor or dexterity impairments:
• It includes people who can have total absence of limbs , paralysis and can have lack of fine control.
• It also includes people who are facing instability or pain in the use of fingers, hands, wrists, or arms.
›
Hearing disabilities
:
• It includes peoples who are suffering from deafness,
• They may range from total deafness (the person is not able to hear at all) to slight loss of hearing (the person can sense sounds and speech).
›
Cognitive disabilities
:
• This is very broad category which includes difficulties in the performance of mental tasks
• These can range from limited and focused problems affecting a very specific cognitive function (the ability to understand math), to severe cases ( brain damage)
›
Speech impairments
:
• It includes people having problem with speaking, it is quite rare but some times it is combined with other disabilities.
• Individuals with speech impairments may have articulation problems (stuttering) be unable to speak loudly or clearly, or even to speak at all.
›
Illiteracy
:
• Illiteracy is the lack of ability to read and write in any language.
›
Age-related disabilities
:
• These are frequently referred to as a separate category, but all related problems fall within the above categories
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In human computer interaction, computer accessibility (also
known as Accessible computing) refers to the accessibility of a
computer system to all people, regardless of disability or severity
of impairment.
›
As we know that computer can be easily accessible for normal
people but for people with several disability can access computer
by using several strategies.
› Disability related accessibility problems are usually tackled through a combination of:
› Assistive Technologies:
• In this technology we use devices that are suitable to some extent for a specific disability.
• Assistive technology is any item, piece of equipment, software or product system that is used to increase, maintain, or improve the functional capabilities of individuals with disabilities.
› Interaction Techniques:
• This technique on the one hand appropriate for the disabled person's interaction capabilities and needs, and on the other hand, can work with, and take advantage of, any available assistive technologies
› Content Annotation and Adaptation:
• So that the content can be easily perceived and can used through the employed assistive technologies and interaction techniques.
The basic strategies for making computers accessible by each
impairment category include.
›
Visual impairments:
If someone is visually impaired this means that they have difficulty in
looking at or reading large amounts of text on a page or are unable to
see objects a far distance away from them. For these types of people
HCI provides different strategies by applying them these people can
interact with computer.
• Content annotation with semantic information.
• Provision of the content through alternative modalities, such as audio and tactile (in the form of Braille).
• Support for content enlargement e.g. control of font size, zooming facilities.
• Customization of color combinations to improve contrast and
simplification of visual complexity (e.g., replacing background images with solid colors) to improve legibility.
• Support of input through the keyboard, Braille devices and speech.
• Ability to serially and hierarchically browse the content and interaction objects in a logical order.
›
Braille Keyboards
In order for a computer to a carry out a required task or activity
the user first needs to enter the information via an input device,
such as a keyboard or a mouse. In order for someone who is
visually impaired to do this, new keyboards have been developed
to help them enter information into the computer. For example, to
save the user looking for the letters on the keyboard new braille
keyboards have been developed and so basically the user will be
able to see through their figures and type a sentence using the
braille as a guide as to what letter they want to select.
›
Motor or dexterity impairments:
Individuals with motor impairments mainly face difficulties in using standard input devices, i.e., the keyboard and the mouse to solve their problem HCI provides different alternatives.
• Use of alternative input devices and techniques, such as switches,
specialized keyboards, mice, trackballs and joysticks, scanning, visual keyboards and speech.
• Speed and timing control and adjustment to suit different response times.
• Ability to serially and hierarchically browse the content and interaction objects in a logical order.
›
Hearing disabilities
:
Deaf people communicate using sign and written language, while very few of them may rely on lip-reading and hearing-aids they may range from total
deafness (i.e. the person is not able to hear at all), to slight loss of hearing (the person can sense sounds and speech, but finds it hard to identify their content) to provide them accessibility to computer we have several techniques.
• Visual representations of auditory information.
• Augmentation of speech with sign language.
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Cognitive disabilities:
This is probably the hardest category since sometimes, depending
on the type and level of disability, solutions must be provided at an
individual basis. In general, all related solutions are.
• Provision of alternative (simplified, illustrated) versions of the content.
• Simplification of tasks, e.g., through step by step procedures and wizards.
›
Speech impairments:
Individuals with speech impairments may have articulation problems (e.g., stuttering), be unable to speak loudly or clearly, or even to speak at all.
Obviously, they have problems in using speech recognition systems.
Depending on the severity of their case, they may use communication aids, to substitute speech.
• Support of alternative input / communication methods when speech is required.
› https://liam900.wordpress.com/2012/10/17/how-developments-in-hci-can-he lp-those-with-visual-impairments/
› http://www.tobii.com/eye-tracking-research/global/research/human-compute
r-interaction/
› http://webhome.cs.uvic.ca/~mserra/indigo/Papers/HCI_final.pdf
› Cress C.J. and Goltz, C. C. (1989) Cognitive Factors Affecting Accessibility
of Computers and Electronic Devices, in Proceedings of RESNA 12th Annual Conference, New Orleans, Louisiana.
Made
By: Muhammad Dawar
