I read the comments about the potential for a navigation device
with a mixture of enthusiasm and concern. I am a very
enthusiastic user of the sort of device you wish for: "... a
very sophisticated sensor array could even build an audio picture
of the immediate environment, much as sonar does for a
submarine." As I discuss below, this aid has been (sort of)
available for 25 years! However, for a variety of reasons, it
has not received wide acceptance, especially in America.
I will give a very potted history of electronic travel aids
(ETAs), together with my biases. I will then make some
summarizing comments.
The first ETA to be built was, to my knowledge, the Sonic Torch.
It was developed in England in the early 1960s. A largish, hand
held device, it used ultrasound to detect objects. Information
was provided to the user by sound through a single earphone. As
the distance between the torch and an object decreased, the pitch
deepened. The quality of sound also varied, depending on the
object. The beam was fairly narrow, so the user had to scan to
detect objects.
The torch set the scene for ETAs by not being a raging success.
The reasons for this are complex. As is the pattern, though, a
small group of people found it very helpful. I read not many
years ago about the efforts of a group in England to maintain
parts for it (I have a Torch minus battery in my garage).
Out of the ashes of the Torch arose the SonicGuide. This was
initially developed at the University of Canterbury in
Christchurch, New Zealand. I was involved in a very early pilot
project with the aid, as a trainee user, in (I think) 1970. The
commercial product was produced by Wormald International Sensory
Aids (later Pulse Data International) in Christchurch several
years later. I was unpacking mine in November 1975, as the
Australian Government was being sacked by the Governor General -
a day still remembered with diverse emotions in this country.
Pulse Data is known as Humanware in America.
The SonicGuide is worn as a set of spectacles (or less usually as
a head band). It also uses ultrasound to detect objects and
converts the signal to sound. However, its signal is stereo and
the beam is broad. A great deal of information is available
about the environment and a small number of users (including me)
continue to derive great benefit from it. However, many people
who received training did not persist with the device. Again,
the reasons are complex. Indeed, having done an honours thesis
on the aid in 1982, I can say with some confidence that we do not
know why some people do well with it and others do not. I can
say that the range of ability among initial users to interpret
the information is very broad. I can also say that poor
cosmetics and comfort play at least some part. Some people may
also say that anything covering my face has to be an improvement.
Seriously, though, I know people who found the information
extremely valuable, but would not use the aid because of its
bulky nature. I should also say that very few people recognize
the aid on me as anything more than a set of spectacles - they
usually assume the cane has electronics in it.
I think it was in the late 1970s that Pulse Data developed the
Mowat Sensor (named after its inventor). This is a small, hand
held device. It also uses ultrasound for detection of objects,
but information is conveyed to the user by vibration. The Mowat
detects the nearest object only. The closer the object, the
faster the vibration. The aid has two ranges, four metres and
one metre.
Due to the much more limited nature of the information provided
by the Mowat, I did not consider using it until I began "playing
with" one five years ago. I began by using it indoors and later
graduated to outdoors. While I can travel faster and more
accurately with the SonicGuide, I can use the Mowat in busy areas
with a good deal of efficiency and comfort. Because of its
convenience, I use it almost exclusively when moving around the
open plan office at work. I usually use either Mowat or
SonicGuide in conjunction with a cane outdoors. The cane, for me
however, is very much the secondary aid.
The Laser Cane was developed in, I think, the late 1970s. One
found its way to Australia, but I didn't get to use it. I
understand that it is still available. As I recall, it uses a
combination of sound and vibration to advise the user of objects.
It, unlike other ETAs, detects drop-offs.
Guide Dogs in Australia were developing the Pathfinder several
years ago. Its inventor, Dr Tony Heyes, then worked for them.
It is a head band aid. Musical notes run down a scale as the
user approaches an object. The distance between notes was, if I
am correct, about 15cm or six inches. That is, distance
measurement is not continuously variable and, rather, is in
steps. The shortest range is, I recall, rather more than half a
metre - more than two feet. That is, anything at that distance
or closer gives the same note. I used the Pathfinder only
briefly. It is of little or no value indoors. I could not
detect low objects (including a bus seat) with it. Perhaps it is
my lack of musical skills, but I found the information vague,
both in terms of direction and distance. This aid is based very
much on the premise of an object detector (see summary below).
Several other ETAs have been developed, but I have not had
personal experience of them either.
Summary:
While a device which warns of an object at a certain distance may
initially have some appeal, my suspicion is that it would be of
very little value in most situations. If you set the distance at
- say - one metre, that would tell you very little in a crowd or,
for that matter, in my office where there is considerable
clutter. Reduce the distance and you may as well use a cane.
Increase the distance and confusion rains supreme.
In the literature over a decade ago, the debate surrounded object
detectors versus environmental sensors. However, most of the
aids I described above are not truly object detectors only. The
Mowat, for example, can tell a thoughtful user much more than
that there is something ahead. You know (essentially) how far
away the object is. By scanning, you also know something about
its size. It is, for example, easy to distinguish between a pole
and a person in a train (an important distinction to make).
Proprioceptive feedback provides information about the exact
direction of the object. That is, the user is, in my view,
ideally taking an active part in deducing what is ahead and
making appropriate decisions accordingly.
One of the problems, it seems to me, is that very few people
really appreciate the potential of the sort of information
provided by existing ETAs. I have read in formal studies of the
SonicGuide, for example, that it will not detect low objects. It
will not always do so, especially in cluttered areas. However,
even in unfamiliar areas, I often do not use the cane to locate
ascending single steps or flights of stairs. That is, I can
locate the position of the step and also judge its height. I
stress that it took me years of practice to be able to do that.
That raises what I see as a crucial point. Many of the people
who ceased using ETAs did so with less than a year of experience.
In this instant gratification society, an apprenticeship
stretching over several years is hard to sell. However, I doubt
very much that something as complex as the environment can be
conveyed at any real level of accuracy to a blind person without
the signals being somewhat complex.
Finally, I strongly suspect that a sophisticated ETA could be
developed much more cheaply than the SonicGuide. The Lawrence
Livermore product may well represent a major breakthrough in this
respect. However, given the checked history, who is going to be
brave enough to attempt it? Whoever it is, they will have to
persuade blind people in much greater numbers than previously
that the aid is viable. That may well involve doing some major
work on shifting people's expectations of themselves. For
example, blind people sometimes complain to me about difficulties
in the environment. When I don't have the problem, due to the
SonicGuide, they say, in effect, "That's all right for you".
That, though, is a topic in itself.
Andrew Downie
On Wed, 17 May 1995, Tim Noonan wrote:
>
> Originally From: da0011@epfl2.epflbalto.org (DAVID ANDREWS)
>
> I received the following message, and pass it along
> to you for discussion, or whatever.
> Maybe Jim Willows can find out about it since he used
> to work at Lawrence Livermore.
>
> Ken, used to be a member in New Jersey.
> Don't know if he still is.
>
> David Andrews
>
>
>
> TO: Tom Fowle, Smith Kettelwell DATE: 5/17/95
>
> FROM: K. Gould SUBJECT: Radar for Blind
> Navigation
>
>
>
> cc: J. Halliday, Humanware D. Andrews, NFB
>
> Just this morning I heard a story on National Public Radio's
> "Morning Edition" about a new, compact, very inexpensive radar
> device that is being developed at Lawrence Livermore Laboratory.
> (The individual being interviewed, the inventor, was named McUen.
> I am just guessing at the spelling of his name.) To summarize,
> Lawrence Livermore has developed and is currently licensing a new
> radar device that can be used as a proximity detector and can be
> set to sound an alarm when objects are at a particular, chosen
> distance away. When produced as an integrated circuit, it might
> cost as little as a dollar. It is small enough to be
> incorporated into such mundane objects as a carpenter's stud
> finder that would locate studs in a wall. It could also be
> installed in an automobile to warn the operator when he or she
> was about to collide with an object.
>
> I have often dreamed of a sophisticated navigation device
> that could assist blind people in navigating, avoiding collisions
> with objects not detected by their canes, or in finding doorways.
> Ultimately, a very sophisticated sensor array could even build an
> audio picture of the immediate environment, much as sonar does
> for a submarine. The invention of this radar device at Lawrence
> Livermore just might make such a device possible. I urge that
> you look into this invention and its applicability and that you
> pass on this information to others who might have the engineering
> talent to exploit this new invention.
>
> Kenneth Gould
>
>
> David Andrews, director
> International Braille and Technology Center
> for the Blind
> National Federation of the Blind
>
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