In Japanese brand's patented solution, a camera constantly monitors the driver's upper and lower eyelids and uses the data to calculate how open the eyes are. The company admits systems like this already exist elsewhere, but they can sometimes return false results by detecting redeye instead of the location of a person's actual eyeball.
To fix this, the automaker adds a further step to search for redeye. If it occurs where skin is already assumed to be, then the system can go back to tracking the accurate location of the eye.
Toyota doesn't specify how it might use this technology, but more accurate data would always be useful. The company wouldn't be the first automaker to work on implementing eye detection, either. For example, General Motors has a pilot program using it to monitor distraction, and Jaguar Land Rover watches a driver's peepers to create the 3d image for its Virtual Windscreen.