PR54(04)

19 November 2004

Scientists develop “electronic eye” for the blind

An effective navigation system would improve the mobility of millions of 
blind people all over the world. A new “eye” developed by scientists in 
Japan will
allow blind people to cross busy roads in total safety for the first time. 
The “electronic eye”, which would be mounted on a pair of glasses, will be 
capable
of detecting the existence and location of a pedestrian crossing, and at 
the same time measure the width of the road to the nearest step and detect the
colour of the traffic lights. This research appears today (19 th November) 
in the journal Measurement Science and Technology published by the Institute
of Physics .

Tadayoshi Shioyama and Mohammad Uddin, from the Kyoto Institute of 
Technology in Japan , have developed a system that is able to detect the 
existence of
a pedestrian crossing in front of a blind person using a single camera. 
When combined with two other techniques the authors have produced, for 
measuring
the width of the road and the colour of traffic lights, a single camera can 
now give the blind all the information they need to cross a road in safety.

Although some crossings make a sound when it is safe to cross, many do not. 
This issue has been tackled in the past. Adaptations have, for example, been
made to the most common travel aid used by blind people, the white cane. 
There are some canes with added functions which use lasers or ultrasound to 
detect
more distant obstacles. One such is the Talking Cane from Sten Lšfving 
Optical Sensors in Sweden. But this technology can’t give information about the
location of a crossing, width of the road or the colour of the traffic lights.

Professor Shioyama said: The camera would be mounted at eye level, and be 
connected to a tiny computer. It will relay information using a voice 
speech system
and give vocal commands and information through a small speaker placed near 
the ear.

The device developed at Kyoto is the final product of a research programme 
that aimed to give blind people all the navigation information they needed to
cross a road from a single small camera. Last year, the authors announced 
that they had designed a computer-aided camera that could measure the length
of a crossing to within one step length - and simultaneously detect the 
colour of the traffic lights. Crucially, it couldn’t tell you where the 
crossing
actually was until now.

Using images from a single camera, the device has a simple structure: 
unlike sophisticated stereo camera systems it does not need camera 
calibration. (The
information is obtained using a 'camera coordinate system,' so separate 
images do not need to be taken to calibrate the device). The length of a 
pedestrian
crossing is measured by projective geometry: the camera makes an image of 
the white lines painted on the road, and then the actual distances are 
determined
using the properties of geometric shapes as seen in the image. Experiments 
carried out by Shioyama and his colleagues showed that the crossing length 
could
be measured to within an error of only 5 per cent of the full length - 
which is less than one step.

Shioyama and Uddin have now made a breakthrough in detecting the location 
of crossings in the first place and added this to their original camera. To do
this they used a calculation called the “projective invariant” which takes 
the distance between the white lines (called the band width) and a set of 
linear
points on the edges of the white lines, to give an accurate way of 
detecting what is or isn’t a crossing in a given image.

They used this technique to analyse 196 images and it proved successful in 
detecting whether there was a crossing present in 194 of them. In the two 
images
where the system made a mistake, it said there wasn’t a crossing where 
there really was one.

Katherine Phipps, Accessible Environments spokesperson at the Royal 
National Institute of the Blind said: Mobility is a serious issue for blind 
and partially
sighted people and new tools like this that may help people with sight 
problems get around safely are always welcome.

- - ends - -

PLEASE MENTION Measurement Science and Technology AS THE SOURCE OF THIS 
ARTICLE, PUBLISHED BY THE INSTITUTE OF PHYSICS . IF PUBLISHING ONLINE 
PLEASE CARRY
A HYPERLINK TO
www.iop.org/journals/mst

Useful Link:

Royal National Institute for the Blind (RNIB)

www.rnib.org.uk

Notes to editors:
List of 4 items (contains 1 nested list)
1. For further information please contact: David Reid, press officer, 
Institute of Physics, Tel: 0044 20 7470 4815, Mobile: 07946 321473, E-mail:
[log in to unmask]
2. The paper ‘Detection of pedestrian crossings with projective invariants 
from image data’ by T. Shioyama and M. S. Uddin will be published online on 
Friday
19 th November 2004 in Measurement Science and Technology (
www.iop.org/journals/mst )
Volume 15, Issue 12, pp 2400-2405 . The paper can be downloaded free of 
charge from 19 th November from
http://stacks.iop.org/MST/15/2400
3. Professor T Shioyama, Kyoto Institute of Technology, Tel: 0081 (0)75 724 
7355. If telephoning, note Japan is 9 (nine) hours ahead of GMT .
4. The Institute of Physics is a leading international professional body 
and learned society with over 37,000 members, which promotes the 
advancement and
dissemination of a knowledge of and education in the science of physics, 
pure and applied. It has a world-wide membership and is a major international
player in:
List of 3 items nesting level 1
• scientific publishing and electronic dissemination of physics;
• setting professional standards for physicists and awarding professional 
qualifications;
• promoting physics through scientific conferences, education and science 
policy advice
list end nesting level 1

The Institute is a member of the Science Council, and a nominated body of 
the Engineering Council. The Institute works in collaboration with national 
physical
societies and plays an important role in transnational societies such as 
the European Physical Society and represents British and Irish physicists 
in international
organisations. In Great Britain and Ireland the Institute is active in 
providing support for physicists in all professions and careers, 
encouraging physics
research and its applications, providing support for physics in schools, 
colleges and universities, influencing government and informing public debate.
list end

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