An everyday story
On an average summer day Mr. Smith, an average visually impaired man, goes into an average library to try to read an average monthly. He goes to a computer and realizes there is no screen reader installed – a screen reader is a software application that attempts to identify and interpret what is being displayed on the screen. No problem he thinks, he goes home and takes his notebook with a screen reader to the library. However the employees of the library refuse this solution suspecting Mr. Smith might be going to launch a publishing company. So he asks the librarians to scan the article he is interested in so that he can read it out with his own computer at home. This does not work either, because the librarians are not allowed to let anything leave the institution in electronic form. Eventually Mr. Smith goes back home with a single copy of the article in print. This situation is neither satisfying nor transparent for both actors: the visually disabled and the librarians.

Visually impaired persons are consumers like you and me
In the European Union there are more than 10 million people who have significant sight loss and are not likely to be able to read printed news. Since average life expectancy is continuously rising, more and more people have impaired sight. These people do not identify themselves as blind or partially sighted, but they are only able to read published materials by using alternative methods.

We have no exact statistical figure about the number of people suffering from dyslexia or about the state of their disability, but according to experts about 4% of the population is severely dyslexic. A further 6% have mild to moderate problems.

Naturally some aspects of the lives of blind people are significantly different from average people, but considering the consumption of (digital) contents they are not different at all. They listen to radio and television, they usually have CD and/or DVD players and they buy films. They are up-to-date with regard to movies, celebrities and series like anybody else. These offerings are essential for them to be full members of society.

In this article we try to give an overview of the technologies which assist the visually impaired in being consumers and users of content, and the accessibility problems they face. It also outlines a solution to some of the problems.

Technology: TTS and screen readers
To use a computer a blind person needs a text to speech engine (TTS) that can read texts out. TTS is responsible for speaking but not what to speak. Under Windows operating systems TTS engines usually support Ms Speech API – which is the standard way to create speaking enabled applications.

A screen reader is a special application which can narrate applications, or screen, or system and keyboard events. It echoes key-presses, appearance of windows and message boxes (even system bubbles of XP). Screen readers do not use OCR techniques. Optical character recognition involves computer software designed to translate images of typewritten text (usually captured by a scanner) into machine-editable text. Screen reader applications are based on special programming techniques, so called hooking, and a lot of heuristics and scripts. Usually it contains a special display driver, which tries to catch/capture the text printing function calls. This application interprets the screen for the blind and speaks out every message by a TTS engine.

There is a small group of applications which are developed for the blind: usually special blind games or learning environments or web browsers. Such software can be used by the blind without any screen reader application. The user interface of these applications is designed for the special requirements of blind users.

Limits and problems of screen readers
The first screen readers applied hooking mechanism (under Windows), but as time went on they became more and more complicated and it got more and more difficult to get textual information off the screen. Some applications even deliberately prevented other applications from getting text from that application. A wide known example is the Adobe Acrobat Reader in its earlier versions.

Furthermore, screen reader software is unable to read textual documents appearing in the windows of that application. This phenomenon is typical for applications which have their own text drawing function. To solve this problem companies like Adobe offer accessibility packs on their websites. After installing such a pack it is possible to read the document aloud from the menu. Later versions (6.0 and later) of Adobe Acrobat Reader have incorporated that function directly. The functionality however is quite poor, because only individual pages or full documents can be read aloud. An up-to-date screen reader software should be able to read out text parts of different sizes (page, paragraph, sentence, word and letters too)!

Microsoft specified the IAccessibility interface as a standard way to give information to screen readers. Unfortunately, this interface is supported by only few applications, because its implementation would mean a lot of "unnecessary" additional effort.

As a matter of piquancy, different by-passes like the one used by Adobe Acrobat Reader do not guarantee to prevent getting content. A professional software developer can develop a fake TTS with just 15 minutes’ work, which instead of reading the text aloud collects it in a file. This manoeuvre can be performed with the IAccessibility interface too. However, as the user interface does not allow reading complete documents aloud contiguously but just in small pieces, this type of attack is made difficult here

From simple voice books to DAISY books
A printed book is available to a blind person by scanning, then transforming the text with the help of OCR software into digital text and reading it out by a screen reader. This long and complicated task can be performed by a blind person after practicing it for a while provided he or she has the needed equipment. We can imagine what an overhead of work this means for each blind person to scan the same book. In practice, blind people share books scanned and transformed into speech, and blind peoples’ organisations collect these materials, tolerated by copyright owners. Some countries allow copying books in that way for people with disabilities provided it is not for profit. Copyright owners tolerate this. However, publishers are more and more afraid, and not without ground, that books digitised in that way can easily be shared via file sharing applications. To digitise a book is hard work. Average users will not start to scan and recognise (by OCR) a hundred-page long book, but if he or she has ready access, that's quite a different story.

In the beginning voice books were recordings available on different media. Then, with the spread of computers they appeared in more and more sophisticated forms. The length of audio files on a single CD was increased by compression. Hybrid talking books also appeared which contained the book in text and in voice form as well making the content capable for key word searching. Talking books are not only for people with disabilities. The value of a literary work can be increased if it is performed by a well know actor.

In this context the DAISY standard is very important. The DAISY Consortium was formed in May 1996 by talking book libraries to lead the worldwide transition from analogue to digital talking books. DAISY denotes the Digital Accessible Information SYstem which is the standard, when we talk about books made for visually impaired. This is a very widespread format used all over the world from the USA to Japan. The secret of the success of DAISY is that it uses a simple open format. Not only player software and devices but various types of DAISY editors are available. Many of them can be used by the blind, so organisations of the visually impaired can make their own talking books. DAISY digital talking books contain the text in XML format plus the high quality voice record synchronised with the text. DAISY books are distributed on CD-ROMs and there are many portable players. DAISY does not make possible either the encryption of information or the identification of users, which is a limitation in terms of DRM, because it relies on these two components. For more details see the DAISY standard; cf. sources). However, many books are published in that form worldwide not only for people with disabilities.

An innovative solution from Hungary
There are solutions which aim to take everybodys’ interests into consideration. "Világhalló" is a Hungarian service supported by Hungarian publishers which started in 1999. Világhalló is an integrated on-line service which forwards available texts as a combined text and voice flow to the user (as a text radio) using special voice-text synchronised protocol (wow) developed specially for this purpose. By the way, "Világhalló" is a play on words which converts the Hungarian name of the Internet to "World Listener". Copyrighted content is stored on a secure server and a client program downloads the voice. This solution has an advantage regarding copyright, because the text alone is not accessible by the user. This is in line with the publishers’ requirements.

"Világhalló" deals with stored text, irrespective of its genuine format (HTML, ZIPHTML, TXT, ZIPTXT, MSWORD, RTF, XML, SGML) and transforms it into a format for best reading aloud. The software adds to the text informative, structural annotations concerning the reading aloud (like sentence, paragraph, strophe, chapter, etc. or foreign word pronunciation even in inflected form).

This system is mostly used by the blind, since it is not really suitable for everyday people. Publishers make some of their copyrighted products available to gain experience. In the early phases of Világhalló it had no users at all, because accessing the content needed continuous broadband Internet access, which meant high cost, especially for the blind. During the last six years, the service has overcome the first difficulties, and now it has 16.000 users. What is more, it has managed to get the full trust of publishers and within a few weeks works published by Magvető, one of the leading Hungarian publishing companies, will become available on Világhalló.

Accessibility issues beyond books
Problems using websites
Questions connected to persons with disabilities are not always technological. Many publicly available free contents are not accessible for visually impaired people, because the content is visually organised in such a way that without seeing it, the text turns into an unembraceable continuum. An excellent example for this is an average news portal. The structure of pages targets the majority of visitors. To make such a portal readable for visually impaired people we have to make many simplifications. Fortunately, contents are stored in databases by up-to-date portal engines so a blind friendly version can easily be produced simultaneously with the normal appearance. Governments could motivate companies to work on these developments by subsidised tenders. In the ideal case, this would even provide work for people with disabilities to be involved not only in testing but in development too.

Problems using software
Access to content is difficult for the visually impaired, but so is the use of software. I do not mean here sophisticated programs like a video editor, but the most essential programs. Many software user interfaces use exotic or mouse optimised controls which can not be handled by screen readers. That would not mean a problem itself if the impaired could choose an alternative solution, another software. The trouble however is, that this phenomena often occurs even in developments targeting visually impaired people! Although there is an ergonomic standard for such applications, many developments don't take it into account. This situation could be avoided if someone really concerned were to work in a developer team, and if the opinions of people concerned were collected in the design phase.

Problems using high-tech gadgets
Most music players use LCD displays to display textual information. This is totally unusable for a visually impaired person. However, many blind people use such equipment, simply memorising the menus and the order of the buttons. Many of the blind, using the same method, are able to even send SMS. The use of mobile phones is one of the challenges facing the vision-impaired. Mobile phones are designed primarily on visual concepts, without considering the needs of the blind or partially sighted. There are some screen reader solutions for mobile phones that allow access to most of the functionality of the device. These are designed to work with the Symbian-based operating system (mostly business class Nokia and some Ericsson, Samsung, Panasonic and Siemens phones). These products allow access to all of the phone's applications, including third-party applications.

Bottom line
The biggest accessibility problem today is that publishers and copyright owners are not, or not really, interested in serving the blind or people suffering from dyslexia. If there were a standard system which ensured copy protection and made content available in digital form, the visually impaired would become a valuable market for publishers.


About the author: Zoltán Nagy is the Head of Development at Speech Technology Ltd. which develops speech processing solutions and has taken part in many projects aiming visually impaired users. For more information see:

Status: first posted 26/01/06; licensed under Creative Commons