Bioengineers at Imperial College, London have developed a new computer controller for paraplegics that is not only more accurate and easier to use than current methods, but also uses inexpensive, off-the-shelf components. The GT3D device uses a pair of eyeglass frames with two fast video game console cameras costing less than UKP20 (US$30) each, which scan the wearer’s eyes from outside the field of vision and provide "3D" control at much lower costs and without invasive surgery.

As computers become smaller, cheaper and more powerful, they gain greater potential for liberating paraplegics and other heavily impaired people. The computer’s potential to enhance the parapelgic’s quality of life is tremendous, but it depends on finding a practical means of control. Everything from air puffs to neural implants called "brain-machine interfaces" (BMI) have been tried, but a team lead by Dr Aldo Faisal, Lecturer in Neurotechnology at Imperial's Department of Bioengineering and the Department of Computing, has taken a new approach that is not only more precise and accurate, but is also much cheaper and uses technology that is already readily available.

Publishing in the Journal of Neural Engineering on Friday, the Imperial College team explained that the GT3D device, as it is called, uses two cameras to collect images of each of the wearer’s eyes. The high resolution of the cameras combined with the gaming algorithms allows the camera to track and process the images with great speed and accuracy. This not only allows for very accurate and precise control of the computer, but it makes it very intuitive to use and wearers were able to play a game of Pong within ten minutes of donning the glasses.

The system tracks both eyes with great precision and accuracy

Because two cameras are used that can see both eyes simultaneously, this adds a whole new level of capability. The two cameras can track the angle of the wearer’s eyes and from that can judge the angle and distance of what is looked at. This means that the control operates effectively in three dimensions as opposed to the two dimensions of single-camera systems. This makes for greater accuracy and the ability to interact with objects in the real world. Equally important, by scanning both eyes the system gives paraplegics the equivalent of a mouse click by simply blinking one eye.

According to the Dr Faisal, the GT3D system is ten times faster than more invasive or intrusive neural systems and many times cheaper. "Crucially, we have achieved two things: we have built a 3D eye tracking system hundreds of times cheaper than commercial systems and used it to build a real-time brain machine interface that allows patients to interact more smoothly and more quickly than existing invasive technologies that are tens of thousands of times more expensive. This is frugal innovation; developing smarter software and piggy-backing existing hardware to create devices that can help people worldwide independent of their healthcare circumstances."

The system is also much faster than BMIs because it operates in real time using a closed-loop control. Furthermore, the 3D aspect of the system opens the possibility of not only controlling computer software on screens, but also of operating wheelchairs or even controlling robotic arms.

A demonstration of the GT3D controller in action can be seen below.

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