PARIS – It is now possible to draw and write using just eye movements, claimed France's National Center for Scientific Research (CNRS).
French CNRS researcher Jean Lorenceau said that subjects suffering from limb paralysis can use their eyes to personalize their writing and express themselves. They can write numbers, letters, figures, their signatures and to draw through a technique based on an oculometer and a computer screen. An oculometer enables eye movements to be recorded by analyzing images of the human eye captured by a camera to calculate the direction in which the subject is looking.
Source: CNRSThe left hand side of this figure shows the position (solid line) and the speed (dotted line) of horizontal (red) and vertical (green) eye movements. On the right: the word “eye” corresponds to these traces.Source: CNRSFigures written with the device
To start with, Lorenceau said he used a visual illusion called reverse-phi. The illusion occurs when several hundred disks whose luminance varies over time at a frequency of around 10-15 Hertz are displayed on the screen. When the subject's eyes move over this flickering background, the subject has the clear impression that the disks move with the displacement of the eyes. Since the human eye can with precision moving objects, the illusory movement of the disks induced by the movement of the eyes gives them a moving support, allowing them to realize regular and non-jerky trajectories, researcher claimed.
An oculometer then records the movements of the user's eye and a software tool enables these movements to be visualized on a screen.
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Lorenceau indicated that only two to four training sessions lasting around 30 minutes are needed to be able to manage eye movements and draw letters. Then, well-trained users can write with their eyes at more or less the same speed as with their hand.
Moving forward, Lorenceau said he expects to propose the system to persons suffering from amyotrophic lateral sclerosis. It could also be used to train pilots, surgeons, sportsmen, artists and other persons whose activities require precise oculomotor control, he concluded. ------------------------
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