Iris technology could soon help electric wheelchair users
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Severely disabled people could soon be able to control their electric wheelchairs by simply looking in the direction they wish to travel.
A team led by Dr Prashant Pillai of Bradford University has demonstrated a prototype that uses an infrared camera headset to capture gaze data and feeds it to the steering motors of a wheelchair.
Commercially available electric wheelchairs generally use a armrest-mounted joystick to control speed and direction. There are models for more impaired users that employ mouth and tongue interfaces, but they are expensive and quite intrusive.
For the current prototype, Pillai simply retrofitted one of the joystick-controlled models to receive wireless signals from a headset. The headset captures gaze data by shining infrared LEDs onto the iris and recording the reflected signals with a CCD camera device and converting the signal into something the steering motors can recognise.
‘When someone sits in it for the first time, it takes a while to train and get used to it, because most of the time we keep looking around everywhere,’ Dr Pillai told The Engineer.
The biggest challenge though was to integrate all the required systems with as little latency as possible, Pillai added.
‘From the technical side we’ve tried to remove all the delays and make sure it’s as real-time as possible, otherwise if you look left and it turns left after two minutes, people will not get used to that.’
Ultimately though, Pillai wants to remove the obtrusive headset entirely, and place infrared-coupled cameras around the front of the chair pointed up at the eyes.
‘The headgear is really just to show it works, of course we don’t expect make someone who’s already disabled to wear this big glasses thing, it’s probably not the best approach.’
The longer-term aspiration is to work towards a fully assisted home, where a users could just look at their television, lighting or music equipment to switch it on.
Readers' comments (3)
Bob Brookes | 30 Sep 2011 3:31 pm
This is nothing new. A user interface system of this type was trialled over 20 years ago. The fully-assisted home was shown at several exhibitions around that time, and wheelchairs with interfaces have been available for many years.
I worked on an alternative system around 1990 in which the chair was equipped with various sensors to avoid obstacles. (Collision Avoidance - an accessory for the Dynamic DX control system.) A severly disabled user merely needed to make some vague indication of direction (operating any kind of sensor) and the chair did the rest. The difficulty is that people who need this type of assistive technology can't usually afford it. There is also the problem to provide adequate after-sales service and support.
The so called sip 'n puff interface where the user can blow into a small straw located near to his mouth works very well and is reliable and cost effective, requiring only a few pressure sensors in a box. It is easy to learn (no operating delays!) and quite unobtrusive. There is no point in re-inventing the wheel!
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Saim Memon | 2 Oct 2011 9:50 pm
I can understand this but the way article written as in first paragraph that
by simply looking in the direction they wish to travel.
Could you define the Wish, An electromagnet signals from minds. How could you manipulate or differentiate the signals that I wish and I wish not..
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Editor's comments | 2 Oct 2011 9:50 pm
To clarify, the wheelchair is controlled by eye movements not brain signals - users have to look in the direction they want to go, not just think about it. However, scientists have been developing thought-controlled wheelchair technology for several years: http://www.theengineer.co.uk/news/the-power-of-thought/303366.article
Chris Dieterle | 14 Oct 2011 9:47 pm
This technology could be adapted and combined with other sensory feedback to assist blind persons in mobility.
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