音声ブラウザご使用の方向け: SKIP NAVI GOTO NAVI

INTERFACING FOR THE BLIND: THE DILE MODEL

Fernando Alonso, Sonia de Frutos, César Montes
Facultad de Inform tica - Universidad Politécnica de Madrid
Campus de Montegáncedo, s/n
28660 - Boadilla del Monte
Madrid
SPAIN
Tel.: + 34 1 336 74 11
Fax: + 34 1 336 74 12
E-mail: falonso@fi.upm.es
ésfrutos@fi.upm.es
écmontes@fi.upm.es

Web Posted on: November 30, 1997


1. INTRODUCTION

DILE is an electronic speaking dictionary for blind or sight-impaired people. These people find it very difficult to access culture and education. One of the main problems is reading, as the information is often written on paper. Although it is translated to Braille or an OCR (optical character recognition) device is used, these methods are neither easy to use nor cheap.

If a blind person had wanted to consult a dictionary or an encyclopedia a year ago, he or she would have used one of these manual methods. But now, they can use an electronic dictionary like DILE. This application uses a voice synthesizer giving the user information to allow him or her to move through the application and listen to the meaning of a word. This application, adapted for blind, means that they can hear what they could not see before.

Like other applications, DILE has a user interface, but this differs in many aspects, because it allows easy interaction for people with sight impairments. It consists of two parts: a visual interface and a voice interface. The principal disciplines contributing to the design of this kind of interface are ergonomics, computer science, psychology, sociology, software engineering and design.

The kind of target application and the characteristics of the potential users must be analyzed to build the model and design the interface.


2. ANALYSING USER TYPES

The principal users of DILE are users with impaired vision. They have special needs due to their disability. Speech recognition and speech output devices allow them to use computers.

This application does not include speech recognition because this technology is still in the research phase. A keyboard and mouse are used as input devices. The special keys of the keyboard are used: function keys, cursor movement keys (Up, Down, Left and Right arrow keys) and usually also the PgDn, PgUp, Home and End keys. But it is possible to work with only cursor keys for moving within the dictionary and the qwerty keyboard for writing the word to search. The other type of input device is the mouse. It is only used by sight- impaired people. A voice synthesizer with a Braille keyboard can also be used as an input device.

Interactive output devices are used to guide the user at all times and show the result of a word search. The voice synthesizer and the screen are the easiest to work. Also it is possible to use a Braille line, Braille printer or normal printer.

DILE's potential users are experts, novices and occasional users. Depending on the user type, the user will receive more or less sound location information. This characteristic is configurable.


3. ANALYSING THE APPLICATION TYPE

The target application is an electronic dictionary. All of the information in the dictionary is contained in a data base. This type of application allows the user to consult the meaning of any word in the dictionary. Also, it will allow different types of searches, like:

  • Direct search of simple words.
  • Direct search of compound words (over one word); in this case the system takes into account both the name of the word and the context associated to the word when searching the dictionary.
  • Search for several words that may be matched to a pattern, for which a series of expansion operators (?, *) are employed to search words that have letters in common.
  • Exploratory search through synonyms or antonyms of a word.
  • Hypertextual search of any word that appears in the definition of a word.

Another property of the application is to show the result of a search. The structure of the dictionary must be preserved. A word is composed of several meanings. Each meaning may or may not have a context, a definition and may have synonyms or antonyms.


4. DILE INTERFACING MODEL

The DILE model is the result of this research. It specifies major design facts for hypertext information retrieval systems interfaces and a set of tested specific navigation and interaction solutions.

The interface communicates with the different parts of the DILE application, such as:

a. Retrieval: is interfaced to the retrieval module, the part of DILE application responsible for dictionary queries and navigation.
b. Sound output: is connected with the voice synthesizer drivers.
c. Visual output: communicated to the user, through the screen, keyboard, mouse and the voice synthesizer.

The interface is composed of four parts. These are:

a. Session control: enables the user to begin and end a session with the DILE application and reports all incidences during the session.
b. Configuration interface: allows the user to configure the following features of the application:
  • Voice synthesizer: choose the type of synthesizer (Braille'n Speak, Ciber 232, Ciber 232 Portatil, PC Hablado) and the connection port, and configure the voice synthesizer operating parameters (volume, speed, tone and ring).
  • Colors selection: modify the colors of the titles, the text and the background of all the elements of the application.
  • Help levels: select the detail level of the help messages during the session.
c. Search interface: allows the user to search words and to show the result of the search.

The possible search types are direct search of a word or compound words, search with expansion operators and navigational search. To show the result of a search, the dictionary information is structured in the following manner. A word is composed of several meanings. Each meaning has a context (empty or not), a definition and may have links to other words.

When a user keys in a word, the system searches for it, and the user does not necessarily have to know the search type that he or she wants to use. If the word is in the dictionary, the application shows a list of meanings of that word. These meanings are classified depending on its context. The user can select one of them and listen to its definition. If the word does not appear exactly as it was written, the system will try to find it by correcting possible spelling or typing mistakes and will show a list of similar words.

The reviser is another application property. With it, the user can read the text of the definition manually, line by line or word by word or spell a word. It is possible to search any word in the definition from the reviser.

d. Help interface: although the application must be very simple, it has a context-sensitive help that provides two types of help, general help and page help.

A simple system of hierarchical menus has been designed to enable navigation, using which any user can move intuitively without having to understand the workings of the application.

Use by the totally blind is just as simple, as, although they cannot use the mouse to move from one option to another, they can manage to operate with the keyboard using four keys. This is possible because the user is informed via voice synthesizer of exactly where he or she is at any time, of what option is active and of what the system is doing at the time.

Only a few keys on a keyboard are needed to work the application. The cursor movement keys are used to move into the menus. With the Up and Down Arrow Keys, we can move up or down in the menu. With the Right Arrow Key or Return Key, we can select an option in the menu. With the Left Arrow Key or Escape Key, we can go back to the last menu.

Usually also the PgDn, PgUp, Home and End keys are used to go to the next page, the last page, the first line or the last line of the menu.

These eight keys have different meanings if they are used in the reviser. The Up and Down Arrow Keys allow the user to read line by line. The Right and Left Arrow Keys allow the user to read word by word. The PgDn, PgUp, Home and End Keys allow the user to read the top line of the next page, the bottom line of the last page, the top and the bottom line of the text, respectively. The Return Key allows the user to search the selected word.

The function keys are required to perform other operations.

FUNCTION KEYS FUNCTION
F1 and F2 obtain general or page help
F3 search a new word
F4 activate/deactivate the synthesizer
F5 and F6 know where we are in the application and repeat the last information given
F7 revise the text of a definition
F8 print a definition in text or Braille format
F9 spell a word

5. THE APPLICATION

This model has been applied successfully to different products, like DILE (Larousse Dictionary for the Blind) and DIRAE (Dictionary of the Royal Academy of the Spanish Language for the Blind). Both of them have been developed by CETTICO (Center for Computing and Communication Technology Transfer).

These two dictionaries are the first electronic dictionaries in Spanish designed specifically for the blind or sight-impaired. They are also the only dictionaries to use typhlotechnical adaptations, such as voice synthesizers and Braille lines.


6. BIBLIOGRAPHY

  • Alonso, F; Antonio, A; Fuertes, J.L.; Martinez, L.A.; Montes, C.: "El Dicciónario para Invidentes Larousse Electrónico (DILE): Una Aplicación de la Enciclópedia Parlante Hipertextual (EPA)". Revista Integración, 21. Madrid. 1996.
  • Alonso, F; Antonio, A; Fuertes, J.L.; Montes, C.: "Enciclopedia Hipertextual para Invidentes (EPA)". Actas del Congreso COMPACC'94. Cuba. 1994.
  • Brown, C.: "Human-Computer Interface Design Guidelines". Ablex Publishing Corporation. 1988.
  • Chignell, M. H.; Hancock, P. A.: "Intelligent Interfaces. De. M. Helander. The Handbook of Human-Computer Interaction". Amsterdam, North-Holland. 1988.
  • Frutos, S.: "Proyecto DILE: An lisis, Diseño e Implementación del Traductor de Formatos". Technical Report. CETTICO. Facultad de Inform tica. Universidad Politécnica de Madrid. Madrid. 1996.
  • Galitz; Wilbert, O.: "Handbook of Screen Format Design". QED Information Sciences Inc. Wellesley, Massachusetts, 1989.
  • Grande, M.J.: "Proyecto DILE: Modelo de Consulta para Diccionarios Hipertextuales". Technical Report. CETTICO. Facultad de Informatica. Universidad Politecnica de Madrid. Madrid. 1996.
  • Sacrist n, C.: "Proyecto DILE: Modelado, Diseño e Implementación de la Interfaz de Usuario Adaptada para Invidentes". Technical Report. CETTICO. Facultad de Inform tica. Universidad Politécnica de Madrid. Madrid. 1996.
  • Sime, M. E.; Coombs, M. J.: "Designing for Human-Computer Communication". Academic Press. 1983.
  • Thimbleby, H.: "User Interface Design". ACM Press 1990.