Tracking eye movements accurately, without a massive amount of lab equipment in tow, is still not easy*. If you try to do it by finding the irises in a digital image of the face, for example, the processing required to cope with high speed movements of up to 700 degrees per second is phenomenal…doing that with any degree of precision still poses difficulties.
Today’s invention is a direct contact eye tracker. I’ve talked before about using a single optical mouse to crudely detect movements of the eyes. Now imagine taking the sensors from a dozen or so such mice and embedding them circumferentially in a soft, transparent ring which is lightly held in contact with the eyelids by an adapted pair of spectacle frames.
This approach, which relies on low-cost, high-precision technology, could be especially useful for people with insufficient manual dexterity to control a joystick or by advertisers interested in where people look as they walk freely around eg a shopping centre. A two-eyed version could compute vergence, at least at close range, and provide information about what’s being observed in 3-D space.
*Predicting the direction of eye movement precisiely and quickly might be done by sensing electrical signals to the eye muscles (When preparing to make an eye movement for example, a copy of the ‘movements-to-be-made-next’ program (efference copy) is used to predict where, and at what, we will be looking next. We then compare this expectation to what actually happens. It’s thought that any discrepancy gives a measure of the extent to which external influences eg anomalous head movements, have occurred). As far as I know, there is no easy way to do this non-invasively.
