A Framework for Blind User Interfacing

1
A Framework for Blind User Interfacing

• Fernando Alonso, José L. Fuertes, Ángel L.
  González, and Loïc Martínez
• Universidad Politécnica de Madrid. Computer
  Science School. Spain
• loic_at_fi.upm.es

2
Contents

• Introduction
• Related work
• Usability Requirements for Blind People
• The Framework
• Case Study Dabin
• Conclusions

3
Introduction
Dual Graphical User Interfaces
General Usability Accessibility Guidance
Usability Requirements for Blind People
HCI Modelling
Framework for Blind User Interfacing
4
Related Work

• Adaptation of an existing application ?
• Application with special-purpose interface ?
• Toolkits like HAWK (Stephanidis et al., 2001)
• UIMS HOMER (Savidis et al., 1998)
• What is needed
• To examine the fundamental accessibility issues
• To define appropriate usability guidelines
• Based on experimental evidence

5
Usability Req. for the Blind
Task Adequacy

• Blind people cannot perform all tasks at the
  current state of technology

Dimensional Trade-off

• Sighted users 21 dimensional access
• Blind users 11 dimensional access

Behaviour Equivalence

• Sighted users interact by direct manipulation
• Blind users interact by other means
• Provide adaptation for each UI object
• Additional actions (messages, )

Semantic Loss Avoidance

• Adapt information provided to blind users
• Avoid losing graphical-only information

Device Independency

• Assitive technologies are not standardised
• Deal with diversity of devices

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Framework
Models
Requirements
FBLIND
Task
Task Adequacy
Guidelines
Domain
Dimensional Trade-off
Dialog
Behaviour Equivalence
Application User Interface
BVCL
Presentation
Semantic loss Avoidance
User
SBIO
Device Independency
Platform
7
FBLIND
Guidelines

• Based on
• Spanish National Standard on Software
  Accessibility (UNE 1398022003)
• International Technichal Specification on
  Software Accessibility (ISO TS 160712004)
• Our experience (gt15 years)

Guidelines
Domain
Dialog
Platform
Presentation
Task
User
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FBLIND
Guidelines
Task Model
Task Adequacy

• The tasks should be checked for incompatibility
  with the capabilities of blind people using
  assistive technologies

Domain Model
Dimensional Trade-off
Behaviour Equivalence

• The sequence of windows and their content need to
  be defined as a series of trees linked by
  transitions between windows
• Define the information about what happens when
  transitions take place between tree levels or
  trees, to be presented to the blind user as
  speech or Braille.

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FBLIND
Guidelines
Dialog Model
Behaviour Equivalence
Semantic loss Avoidance

• Keyboard (or equivalent) as main input device
• Define each user interface objects interaction
  process and the access mechanisms to properties
• Incorporate additional interaction commands
  location, repeat, spell, etc.

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FBLIND
Guidelines
Presentation Model
Behaviour Equivalence
Semantic loss Avoidance

• Define speech and Braille presentation of each
  user interface objects (standard and specific)
• Define several detail levels so that the
  interface is suited for both novice and
  experienced users
• Pay special attention to non-standard objects and
  objects with a high graphical content to assure
  that no semantic information is lost

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FBLIND
Guidelines
Platform Model
Device Independency

• Platform should provide Speech and/or Braille
  output
• Provide standardized and documented APIs

User Model
Semantic loss Avoidance
Device Independency

• Individualisation of Speech (speed, tone, volume,
  )
• Individualisation of Braille (cursor type,
  Braille code, )
• Help level (novice, intermediate, advanced)

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FBLIND
BVCL

• Extension of Visual Component Library (Borland)
• User interface objects with automated
  presentation in speech and Braille
• Easy programming of additional speech and Braille
  output
• Easy configuration of specific output messages
• Layout managers

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FBLIND
BVCL
14
FBLIND
SBIO

• Ms Windows platform
• Development Microsoft, ONCE, UPM

Application 2
Application 1
Application N
Application 3
...
SBIO-Lib
Screen Reader
SBIO-Core
SAPI
BAPI
SAPI Driver 1
SAPI Driver 2
SAPI Driver M
BAPI Driver 1
BAPI Driver 2
BAPI Driver P
...
...
Voice Device 1
Voice Device 2
Voice Device M
Braille Display1
Braille Display2
Braille DisplayP
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Case Study Dabin

• Environment that includes bilingual dictionaries
  with a dual and multilingual user interface
• Basic function to search for words in one
  language and get their full translation in
  another language
• Users can choose
• Bilingual dictionary
• Source and target languages
• User interface language
• Visual appearance

16
Case Study Dabin
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Conclusions

• Dual interfaces can satisfy both sighted and
  blind users
• There are specific usability requirements for
  blind users
• We have presented FBLIND
• A set of guidelines, related HCI models
• A toolkit for auto-adapted dual applications
• An API for the use of assistive devices
• Case study Dabin
• Future
• More tool support for other models
• A CASE tool covering the whole user interface
  development life cycle, providing support for
  manual tasks

18
A Framework for Blind User Interfacing

• Fernando Alonso, José L. Fuertes, Ángel L.
  González, and Loïc Martínez
• Universidad Politécnica de Madrid. Computer
  Science School. Spain
• loic_at_fi.upm.es