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Research into Assistive Technology for Visually Disabled Persons

J M Gill

European Union funding has acted as the catalyst for a significant increase in activity in the development of assistive technology.  At the same time dramatic changes are occurring in the available technology particularly in telecommunications.  However there are still major hurdles to overcome before the results of these projects will be of practical benefit to visually disabled persons at affordable prices.


One aim of Royal National Institute for the Blind (RNIB) is to stimulate and coordinate technological research and development to benefit visually disabled persons.  This involves determining priorities since there are finite resources - both in skilled manpower and finance.  To do this implies having access to basic information about the field, as well as implying an assessment that the potential products of the research will be of real benefit to visually disabled persons.  RNIB has neither the resources or expertise to undertake these activities alone since this has an international dimension.  Therefore we have been collaborating on a number of European and international activities.  The Commission of the European Union (EU) is concerned about these areas and is injecting funds to stimulate new activities; this is happening at a time when the UK government is cutting back on expenditure in this area.

RNIB's need for information had significant overlap with those of the Commission of the EU.  The first need was to find out who is doing research and development on assistive technology and what they are doing.  This resulted in a database which has about 5000 entries.  Another need is for information on devices already developed.  The European Commission is setting up a multi-lingual database, called Handynet, which will contain details of devices which are available in Europe.  Distribution is on CD-ROM with two versions of the retrieval software (one with a graphical user interface and one text-based).  Moorfields Eye Hospital and RNIB are responsible for data collection of British equipment for visually disabled persons - this includes low vision aids.

The next stage is to find out how research reaches the user, and then to identify what can be done to facilitate this process.  This is important since very little of the research in the UK has resulted in products available at affordable prices.  The European Commission has similar concerns but with a wider view, so they established the TIDE (Technology Initiative for Disabled and Elderly persons) programme.  Within TIDE, a project was set up to study this problem, and generate models of the process so that an assessment can be made of various strategies for improving the transfer of research to viable products.

TIDE is also investigating:
(a)           Standards, testing and certification of products for disabled persons.
(b)           Communication and cooperation between industries involved in assistive technology.
(c)           The process of service delivery including the training of disabled persons in the use of rehabilitation technology.
(d)           Legislation (eg should there be a European equivalent of the Americans with Disabilities Act, and if so what form should it take?).
(e)           The training of staff in rehabilitation technology.  This is quite well developed in the UK in the area of physical disability but almost non-existent for technical staff in the area of blindness.
(f)            Identification of new technologies which could benefit disabled persons.

The area of priorities for future research was also studied by a number of Concerted Actions which held a large number of workshops focused on specific topics related to technology for people with disabilities.  These workshops included people from the disability field, scientists and engineers with little previous knowledge of disability but with some relevant expertise, as well as disabled consumers.  One side effect of these workshops is that those working on technological research for visually disabled persons came to know each other very well, and this has had a knock-on effect on international collaboration.

Studies of technology trends are being done by other groups (such as COST 219 and the World Blind Union Research Committee).  COST 219 is a grouping of 18 countries - their area of interest is telecommunications and disability.  One of RNIB's activities is to analyse the outputs of these studies and identify the areas of consensus.

An example is the distribution of textual information for blind persons in digital form.  This involves there being some standards for the data format which must be such that it facilitates easy searching, browsing and reading by a blind person with a variety of output modalities such as braille or synthetic speech.  Structures such as hypertext often require intervention to convert the raw text to an optimal structured file - this adds to the cost.  A separate matter is the method of distribution - this could include floppy disc as well as telecommunication links which will come increasingly attractive when higher capacity lines are generally available to domestic users at a reasonable price.  The Tide CAPS project is studying the possible application of a standard generalised mark-up language as a first step in developing a user-friendly system for blind persons, and the Tide ACCESS project is studying user-adaptable interfaces for hypertext and hypermedia systems.

For many software houses, user-friendly computer interfaces mean GUIs (graphical user interfaces).  In the medium term, new operating systems, such as the next version of X-Windows, will have “hooks” which will assist in the development of adaptations for blind persons.  A “hook” is a technique in computer programming to assist the software developer access parts of the system.  In the long term, the situation appears likely to deteriorate because of the development of “locked” operating systems; for commercial reasons these systems will be designed to be inaccessible for software developers.

GUIs will be used in other applications than access to conventional computer systems; for instance "smart housing".  The area of smart housing for disabled persons is of great interest to the governments of a number of countries.  The reason being that they have done a simple calculation of the number of disabled and elderly persons by the turn of the century, and the number of people in work at that time who will be paying taxes.  This calculation has led them to conclude that a greater percentage of elderly and disabled persons will have to be able to live independently, and they foresee that the appropriate use of smart housing will make this economically possible.  Therefore it is important that the design of the man-machine interfaces for smart housing takes into account the needs of visually disabled persons.  For instance it would be technically possible to have a family of controllers designed for the needs of various groups of disabled persons.

One piece of domestic equipment, which cannot be adapted for blind persons just by changing the interface of the controller, is the television set.  However audio description of television programmes has proved popular in north America and Japan.  The audio description of the action of the programme is inserted in the gaps in the dialogue.  The technical problem is that, in Europe, there is not a spare audio channel for transmitting the audio description.  Therefore other methods are being investigated, but with the most promising option being to use two lines of the vertical blanking interval.  This is another project being funded by Tide since it would require an European market to justify the development cost of the chip to be used in the receivers.

The storage of audio information has long been of importance to blind persons.  Problems with conventional compact cassette systems have included controlling the speed of playback and indexing.  Compressed (and expanded) speech chips have been around for some years, but relatively few tape recorders include this facility.  Compressed speech involves speeding up playback without the associated increase in pitch.  Although various methods have been devised for indexing, none could be described as being ideal.  Therefore the advent of digital storage (eg compact disc) offers exciting possibilities since it is capable of giving excellent audio quality in addition to sophisticated facilities such as compressed speech and indexing.  It would also be relatively simple to incorporate circuitry to partly compensate for any hearing loss of the user.  However there is a significant problem in that compact disc (CD) type technology could be superseded by solid state recording at some date in the future.  Therefore the investment in CD type technology has to be written off before the time that any new technology means that the manufacturer will no longer support the old CD technology.

Developments in telecommunications may also have an impact in this area.  For instance it would be possible to consider audio books stored on a central computer and transferred to the user's machine over the telephone line.  Over conventional copper wires a typical novel would take 20 minutes, but a fibre-optic connection could reduce this time to about 20 seconds.  However it is likely to be a long time before the average elderly person has a fibre-optic connection to their home unless they are connected for other purposes (eg cable television).

Despite considerable effort devoted to the technological development of electronic mobility aids, their market penetration has been very low.  In recent years, there has been more interest in orientation and navigation systems.  Typically these involve infra-red transmitters which are modulated with a speech message.  The blind user carries a small receiver which gives the speech message via a loudspeaker or an earpiece.  The transmitters are typically mounted at street corners, on light-controlled pedestrian crossings (to give the status of the lights), and on buses (to give the destination of the bus).  A different approach is to use tag technology as used in shop security systems.  In this case, the tag indicates to a machine the presence of a blind person and the facilities they require; the tag may be pre-coded or controlled by the user.  In effect, this is a form of contactless smart card.  The whole area of smart cards is changing rapidly, and there is potential for considerable benefits to visually disabled persons if the relevant standards allow for their needs.

There has been interest in utilising geographic information systems which are being developed for the sighted population (particularly for car drivers). Many of these systems not only include geographic information but also information such as timetables for public transport.  Positioning information can be obtained from differential global positioning systems which typically have an accuracy of 10 metres.  These systems require line of sight to the satellites which can be problematic in city centres; the usual method of alleviating this problem is to incorporate an inertial navigation system to cover any ‘outing’ of the radio signals.

In the longer term, technological developments in other fields could have benefit for those working with visually disabled persons.  For instance, virtual reality technology could provide realistic simulations of visual defects including fields, acuity, colour discrimination and effects of illumination;  in addition, multiple handicaps could be simulated.  Such a system might be useful for evaluating proposed public buildings.

There is a danger of there being an increasing mismatch between research being done and the needs of the users.  For instance, ten years ago the main users of synthetic speech devices were blind computer programmers as an aid to employment, but in the next few years older blind persons will need to use speech output devices to control domestic equipment such as microwave ovens.  It is not obvious that those working on speech technology appreciate that 35% of the visually disabled population have a hearing deficit.  Therefore there is an important role for consumer organisations in ensuring that system developers are aware of the present and future unmet needs of visually disabled people.


ADA                       Americans with Disabilities Act
CD                          Compact disc
CD-ROM               Compact disc - read only memory
COST 219             Future telecommunication and teleinformatic facilities for disabled and elderly people
EU                          European Union
GUI                        Graphical user interface
RNIB                     Royal National Institute for the Blind
TIDE                      Technology Initiative for Disabled and Elderly people



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