john Gill technology header image

Technological Developments for Blind People

John Gill


In the last ten years there have been significant advances in technological methods for accessing information by blind people.  However in many other areas, such as inexpensive devices for daily living, progress has been very slow.  Another area beginning to attract interest is the design of terminals for the general public so that disabled people are not unnecessarily excluded from using these systems.

Devices for Daily Living
The majority of blind people, in both rich and poor countries, do not have access to high technology devices, and have to rely on inexpensive devices such as simple magnifiers and home-made methods for labelling tins of food.  In many ways life is becoming more difficult; for instance food increasingly comes is standard size packaging which is often very difficult to open.

This is not the glamorous end of research for blind people so it is largely ignored by university-based research workers.  The commercial companies have also rejected developing low technology devices because it is difficult to make a profit from selling low cost products to a specialist market.  Therefore there is a need to develop new mechanisms for the imaginative development and marketing of this type of product. 

Mobility and Orientation
The long cane remains the most common mobility device.  Although numerous electronic mobility aids have been developed over the last twenty-five years, none have proved popular with more than a handful of users.  The problem would appear to be that the extra information provided by such devices may be useful but does not outweigh the disadvantages of using the device; one common complaint is that auditory output from the device masks ambient auditory information.

In the last few years there has been increasing interest in orientation systems.  These fall into two groups: ones which require modification to the environment, and ones which piggyback on systems already installed for other purposes.  Examples of the former are infrared and radio beacons mounted at strategic positions; the blind person has a small hand-held receiver which gives an audible message such as the name of the street, the status of traffic lights or the destination of the bus.  These systems normally perform well, but the high cost of installing and maintaining the large number of transmitters has prevented their widespread adoption.

The other type of orientation system uses existing infrastructure.  One approach, which may have practical relevance in the long term, is to use satellite navigation systems (such as the American Global Positioning System) coupled with an electronic map of the area.  This may sound very futuristic but there have been successful pilot schemes with blind people using such systems for orientation in unknown environments.  An essential aspect is that precise digital maps must exist for the area; this is not a problem in the UK since there are already such maps for the whole of the country, but availability has proved problematic in other countries.  In experiments in Birmingham, blind people found that the system gave them 2 metre accuracy for about 75% of the time.  Further development is needed before such systems can be considered of general practical use for blind people.

Access to Information
Over many years, work has been done to develop electronic reading aids for blind people.  The earliest viable system was the Optophone which converted the shapes of printed characters to musical notes.  Nearly fifty years later came the Optacon which presented printed characters as a tactual vibratory image.  Both these systems required the user to recognise the shape of individual characters.

Optical character recognition is now a viable alternative, and so the output can be in synthetic speech or braille.  As yet the standard OCR systems cannot cope with handwritten material.

However it is the dramatic increase in power and decrease in cost of personal computers which has had the greatest impact.  Early personal computers used text-based operating systems, such as DOS, which was relatively easy to convert to speech or braille output.  However these were superseded by graphical user interfaces, such as Microsoft Windows, which made life more difficult for blind computer users.  Although there are a number of non-visual access systems for the common GUIs, they could not be described as easy to use by the non-technical user.

The advent of the world wide web has the potential of significantly increasing direct access to information by blind people who can afford the cost of a terminal and the service charge.  Access to the world wide web is limited by the design of some web pages and the design of browser software with non-visual output.  Some web pages are almost meaningless if one removes the graphical elements; one possibility is to educate web page designers to provide alternate textual descriptions to all graphical elements.

What about the Future?
The tape recorder has been one of the most useful aids for many blind people.  Recorded books have proved to very popular in many countries.  Unfortunately the technology is beginning to show its age so new delivery systems have to be considered.  Modern digital systems can give much better audio quality than the present systems, and sophisticated methods of indexing can be incorporated.  A new system being adopted by some blindness organisations is based on XML (ie similar to the structure used for multi-media on the world wide web).  This approach means that the spoken word can be directly linked to a textual version of the content.

Virtual reality looks as if it will play an increasingly important role.  In non-immersive virtual reality the user does not wear a headset, but can navigate through virtual space on a screen.  For instance an information kiosk in a shopping centre may have a screen and a joystick, and the user can explore the shopping centre from the kiosk.  However virtual reality can be used in other ways, so that information normally displayed visually is output in audio or tactual space; this has exciting possibilities for blind people.

A different use of virtual reality will be to model buildings prior to their construction, and then explore the buildings as if one had a variety of visual defects.  In addition one could superimpose the effect of various low vision aids, or alter the lighting or colour scheme of the building to investigate the problems faced by partially sighted users.  It is far less expensive to model a building in virtual reality, than to build it and find it does not meet accessibility requirements.

For many years scientists have addressed the problem of how to use electronic systems to replace some of the functions of the human eye.  Up to recently these were just interesting laboratory experiments, but new developments in electronics and wearable computers could turn these prototypes into devices of practical benefit at affordable prices.

The three main approaches are:

Vision enhancement involves input from a camera, processing of the information, and output on a visual display.  In its simplest form it may be a miniature head-mounted camera with the output on a head-mounted visual display (as used in some virtual reality systems).

A more sophisticated system might have a combination of visual and ultrasonic cameras.  The ultrasonic camera can provide information about the distance of an object from the camera.  The user could then instruct that he or she is only interested in viewing items less than 2 metres away.  The processor would then delete all data more than 2 metres; this would significantly reduce the clutter on the visual display.

Another possibility could be that the user is looking for a post box which he knows is painted bright red.  He could request that anything which is not red is shown with lower brightness.  Yet another possibility is for the user to instruct that only the edges of objects should be displayed.  There are many other possibilities for processing the information to meet the specific needs of an individual at that moment.

Vision substitution is similar to vision enhancement but with the output being non-visual – typically tactual or auditory or some combination of the two.  Since the senses of touch and hearing have a much lower information capacity than vision, it is essential to process the information to a level that can be handled by the user.

Vision replacement involves displaying the information directly to the visual cortex of the human brain or via the optic nerve.  Affordable vision replacement systems is some way into the future since much more needs to be known about how to optimally connect to the visual cortex.  Since this will involve a surgical procedure, there will need to be stringent testing to ensure that there are no adverse effects.

In other areas new technology offers the possibility of new services.  For instance the introduction of digital television, makes it easier to provide additional services such as audio description and real-time sign language interpretation of programmes.  Audio description involves a verbal description of the relevant visual part of  the programme in the gaps in the dialogue. The change to digital television in the UK has given us the opportunity to improve the visual quality of the text on the screen; RNIB was involved in designing a new typeface for this application.

With new technology for the general public it is essential to ensure that disabled people are not unnecessarily excluded from using these systems and services.  Often all that is required is a minor inexpensive change to the specification but this must be done before the system is developed. 




John Gill Technology Limited Footer
John Gill Technology Limited Footer