5.3 The Historical Development of Travel Aids for Visually Impaired and Blind People |
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Figure 5.4. Assistive technology system block diagram
shown in Figure 5.4 and this is usually specialised for the particular system under discussion. Further background material on the CAT model is given in Chapter 1 where it is introduced and explained.
5.3The Historical Development of Travel Aids for Visually Impaired and Blind People
Historically visually impaired people have used a number of different methods and tools to support mobility. From the earliest times blind and visually impaired people have used sighted guides, trained animals and simple devices, such as sticks, to give them varying levels of mobility. However, the development of assistive technology systems that will enable all blind people to travel with the same confidence as sighted people is a complex multi-factor problem.
For centuries, visually impaired people have used some form of stick for probing when travelling. However, the long cane, which is currently the most popular device, did not come into widespread usage until around 1950. Guide dogs were first used in the 1920s in Austria (see Figure 5.5).
The first electronic mobility aid, Noiszewski’s Elektrftalm, was developed in 1897. However, serious developments occurred after the Second World War and through the 1950s and 1960s. Once the potential applications of remote sensing by using ultrasound and infrared radiation were realised, research effort was directed at obtaining environmental information using these technologies. Early ultrasonic mobility devices include the Franklin Institute Electronic Cane, Mowat Sensor, and the Pathsounder. Throughout the 1960s and 1970s, obstacle detection devices continued to be developed using a variety of sensing technologies. The
178 5 Mobility: An Overview
development of lasers allowed the so-called “Laser canes” to be produced (see Figure 5.5). Table 5.1 shows a survey of the details for a number of these obstacle detection devices.
In the last decade there has been increased interest in devices to support orientation and spatial sensing. The systems developed include ‘Talking Signs’ and ‘Sound Buoys’, which transmit a remote signal, for instance using infrared radiation. When a traveller moves into the vicinity of the device, the device gives the user an audible warning. These systems have proved to be successful, but installation can be expensive. There are currently many different research projects worldwide looking into different forms of access to mobility and orientation information for visually impaired people. These involve technologies and applications as diverse as ultrasonic systems, infrared systems, GPS technology, sound signs, vision substitution systems, vision enhancement technologies, cell telephony and computer network technologies.
To date assistive technology systems for mobility, orientation and navigation have been developed largely independently of each other. Consequently, users often require separate devices to carry out different parts of the travel process. In addition, some of the devices are quite cumbersome, which has probably contributed to poor take-up. However, advances in signal processing, information and communications technologies, ultrasonic technology and device miniaturisation make the development of a small size multi-purpose assistive technology system a realistic possibility. However, this will require a change in the direction of research effort to focus on the development of a holistic travel system for visually impaired and blind people. This system would have both obstacle avoidance and orientation capability and would incorporate interfaces to the modified built environment to remove barriers to mobility.
Figure 5.5. Historical trends for mobility devices (Li 2001)
Table 5.1. Survey of obstacle detectors
Device name |
Approx. |
Technology |
Body position |
References and notes |
Current availability |
|
year |
|
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|
Sonicguide |
ca. 1965 |
Ultrasonic |
Head worn |
Bat K sonar cane |
ca. 1965 |
Ultrasonic |
Clips onto long cane |
Pathsounder |
ca. 1966 |
Ultrasonic |
Neck worn |
Mims device |
ca. 1970 |
Infrared light |
Head worn |
Mowat sensor |
ca. 1970 |
Ultrasonic |
Hand-held, torch-like |
Laser Cane™ |
ca. 1970 |
Infrared system |
Hand-held cane |
Polaron |
ca. 1980 |
Ultrasonic and ranging |
Hand-held torch format |
|
|
(sonar) system |
or chest position worn |
Sensory 6 |
ca. 1980 |
Ultrasonic and ranging |
Head worn |
|
|
(sonar) system |
|
Wheelchair Pathfinder |
ca. 1980 |
Ultrasonic and |
Wheelchair mounted |
|
|
Infrared systems |
|
Sonic Pathfinder |
ca. 1990 |
Ultrasonic |
Head worn |
Ultra Cane™ |
ca. 1990 |
Ultrasonic |
Hand-held cane |
Tom Pouce |
ca. 1990 |
Infrared system |
Cane mounted |
Teletact |
ca. 1990 |
Infrared system |
Hand-held/Cane mounted |
Miniguide |
ca. 1998 |
Ultrasonic |
Hand-held |
Kay 1974, 1980; Jacobson, 1979 |
Discontinued |
BFB 2006 |
Commercially available |
Russell , 1966 |
Not available |
Mims 1972 |
Prototype only |
Farmer and Smith, 1997 |
Not known |
Benjamin, 1968; Benjamin et al. 1973; |
Commercially available |
Blasch et al. 1989a,b; NR 2006 |
|
NR 2006 |
Commercially available |
Farmer and Smith 1997; BRY 2006 |
Custom orders |
NR 2006 |
Commercially available |
Farmer and Smith 1997; Heyes 1993 |
Not known |
See Chapter 6 of this volume and the |
Commercially available |
references therein; UC 2006 |
|
Farcy et al. 2006 |
Commercially available |
Farcy et al. 2006 |
Commercially available |
GD 2006; GDP 2006 |
Commercially available |
People Blind and Impaired Visually for Aids Travel of Development Historical The 3.5
179