PhoneAbility

Designing for Accessibility

Julian G Jones

juliang.jones@btinternet.com

Slide 1
Designing for Accessibility

• Acceptable (The purpose of the system must be acceptable)
• Usable (The system must be well designed and easy to use for all users)
• Accessible (Accessibility must be designed in from the start. It is expensive to add accessibility features later in the design process.)

Slide 2
Are biometric systems different?

• Subjects must be present to register their biometric information
• Biometric features are fixed but change slowly. (We cannot change our faces or fingerprints on a daily basis but they change as we age.)
• Surgery or injury may change a biometric feature and require re-registration
• Subject groups vary - age, ethnicity (Some older women's fingerprints are difficult to capture.)
• May not require any conscious action (It is unclear what a subject needs to do and how they should behave if the process fails.)
• No absolutes (Two different biometric samples from the same person will not be a perfect match.
• It is a question of setting a percentage of probability. The designer has to consider several factors including the level of security when setting the appropriate percentage of probability.)

Slide 3
Biometric technology

• Biometric samples vary
• Balance of probabilities
• Environment is a factor (Lighting, temperature and humidity can affect the quality of samples.)
• Data is encrypted in most systems
• Cannot be read by a human technician (The biometric data is parameterised and encrypted so it is difficult to determine the reason for a failure to match samples.)
• Reference samples may be held on a chip or in a database (In the case of a sample on a chip the match will be one to one. Identification of an individual from a database is likely to be more complex and may introduce delays before the system responds.)
• Identification or verification

Slide 4
Acceptable Systems

• User acceptance is vital (without cooperation from users the system unlikely to be successful.)
  • Understandable
  • Simplify tasks
  • Increase productivity
  • Save time
  • Maintain privacy
  • Ensure security of information and users
  • Voluntary or mandatory (As long as users accept the purpose of the system it makes little difference to them whether it is mandatory or voluntary.)
  • Affordable for the operator and the subjects (A system which is unaffordable for users may lead to social exclusion.)

Slide 5
Usable Systems

• Attended or unattended (Good design, high availability and help information is vital for unattended systems.)
• Simple consistent interface features
• Clear typeface
• Logical flow of actions
• Clear prompt for the next action
• Errors, warnings and help
• Reset, Cancel or escape (It is essential to be able to reset the system if the user knows they have not presented the biometric sample correctly, for example: the user has presented the wrong finger.)
• Standard icons and symbols (must be clear and it is wise to use standard symbols where they are available.)
• Use of branding (Biometric interfaces will be unfamiliar to most users. Branding should not be so dominant that it obscures the essential features of the interface.)

Slide 6
Environment and physical features

• The equipment site must be accessible
• Signs must be clear
• The position of the subject (This may be critical for success and must be achievable by people with disabilities.)
  • Facing the equipment
  • Correct distance
  • Height
  • Posture

Slide 7
Environment and physical features

• Impact on different biometric technologies and the subject
  • Lighting
  • Markings on the floor (Footprints indicating a standing position are of little help to a wheelchair user or people with visual disability.)
  • Angle and position of a fingerprint reader
• Multimodal biometric systems
  • May require the user to move position (One position may be necessary for face recognition and a second to give a fingerprint.)

Slide 8
Designing Accessible Systems

• Consider the potential users
• Unwelcome surprises (Users must be informed of changes to the interface or new feature.)
• Store user's preferences
• Offer alternatives
  • Languages
  • Font size
  • Colour combinations
  • Speech and audible feedback
• Speed of interaction (Some users take longer to respond to prompts.)
• Feedback on progress (Give clear indication that an event has occurred or an attempt has failed and what happens next.)

Slide 9
Designing Accessible Systems

• Consistent position for features
  • Must be within reach
  • Finger print reader
  • Card slots and keypads
• Retain standard features (If they are required these features will be familiar and build confidence.)
  • Keypads
  • Function keys
  • Standard tactile symbols
• Smart Cards
  • Contactless card (Can avoid some problems for users who have dexterity problems. They also allow a user's preferences to be detected before any other interaction has taken place.)

Slide 10
Explaining the System

• Test the system with representative users
• Information (leaflets and notices.)
• Education for operators, attendants and subjects
• Opportunities for familiarisation (Sometimes called "playtime".)

Slide 11
Support for biometric subjects

• Attended Systems
  • Well trained attendants
  • Understanding of disabilities
• Unattended Systems
  • Access to help
  • Alternative processes and procedures
• Resolution of false recognition or rejection (There must be a contact available to resolve these conditions. This is particularly important for unattended systems that may be used at unsocial hours.)

Slide 12
Registration of subjects

• Registration takes time
• Security requirements
  • supporting documents
• How many registration sites
  • accessible transport
  • accessible building
• o Attended registration (Registration should always be attended to explain the process.)
• Cost of registration and re-registration
  • who pays?
• What happens to users who are unable to register? (Users should not be excluded from essential systems and services.)

Slide 13
Summary

• Experience is limited (Very few systems have been deployed for use by large numbers of the general population.)
• We are all learning
• Share experience (It is important to be in contact with other's working on biometric systems and standards.)

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