These New Robotic Headlights Dodge Raindrops

Further proving the idea that in the future we'll be driving clusters of robots that have grudgingly agreed to drop us off somewhere, Carnegie Mellon University researcher Srinivasa Narasimhan has developed a new smart headlight system that prevents glare in the rain by actively dodging the droplets of water.

Conventional headlights just fling their light forward, in a pattern, but passively, like a can of spray paint. In the rain (or snow), that means a great deal of light gets reflected back to the driver from the rain droplets/snowflakes, and this causes glare and a marked decrease in night visibility. We've all been in heavy rain at night, and know how bad it can get.

Narasimhan's system can track individual water drops, and dynamically aim the beams of light to shine where the system determines the drop won't be. It's sort of the opposite of tracking something with a spotlight. They system uses a camera and an off-the shelf DLP (digital light processing) projector. Currently, the system can react in about 13 milliseconds, but they're working to make the response even faster. Eventually, an array of controllable LEDs would be used for best results.

Even at current response speeds, the headlights eliminate 70-80% of visible rain during a heavy storm, at a loss of only 5-6% of overall illumination. Plus, even if everything goes wrong, Narasimhan has an answer. "If it fails, it is just a normal headlight."

It's not entirely perfect, though.

"Unless it's a waterfall or something that occupies the entire volume in front of the headlight, it should be okay," says Narasimhan, which is bad news for all you night-waterfall driving enthusiats.

(Additional sources: Popular Mechanics, Photonics)