Iris technology could soon help electric wheelchair users

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.