Eye-tracking technology allows people who are unable to type or manipulate a mouse to use a computer. While a camera captures their eye movements, they can move a cursor with their gaze or type on an on-screen keyboard by staring at individual keys. But darting the eyes around like that can be dizzying, and it’s a slow process.
A new gaze-operated text-entry system called Dasher is faster, more accurate, and easier to use than existing systems, say its inventors in the Aug. 22 Nature.
“Eyes didn’t evolve to push buttons,” says coinventor David J.C. MacKay of the University of Cambridge in England. Rather, eyes are good at searching. Dasher is like a fast-paced video game where the user hunts for letters. Each letter is in a box sized according to the letter’s frequency in written English.
After a user chooses each letter in a word, the system predicts the probability of the following letter and resizes the boxes accordingly. More likely letters are in larger boxes that draw the eye. A person’s gaze at a box selects that letter. The system takes advantage of the predictability of normal language, MacKay says.
The researchers tested Dasher against a gaze-operated on-screen keyboard. Using Dasher, people could write up to 25 words per minute, compared with only 15 words per minute using an on-screen keyboard. Dasher users also committed far fewer errors.
Besides eye-tracking computer setups, any pointing device, such as a mouse or touch-screen wand, can drive Dasher, MacKay says. “People find it fun to use.”