Carnegie Mellon Researchers Beat Headlight Glare with DLP Headlights

It’s a common rule: the brighter your headlights and the harder the rain outside, the more those headlight beams reflect against the raindrops. Not so fast: researchers at Carnegie Mellon University say they’re working on a solution that could make raindrops nearly invisible while lighting the road in front of you.

The problem CMU researchers are trying to solve is that headlight beams are reflected back at the driver when it rains, snows, sleets, et cetera. The brighter your headlights, the brighter the light is reflected back at you, and the harder it is to see the road ahead of you.

CMU’s possible solution involves a camera, a digital light processing (DLP) projector, and a reflecting mirror, alongwith a computer to control the whole setup. As rain falls, the camera can detect individual raindrops and predict where and how they’ll fall. It sends that information to the projector, which projects a small black dot over each rain drop’s location. The result, researchers hope, is the ability to light in front of the car but not the raindrops, which would result in high light throughput with little reflection.

Not surprisingly, it’s very hard to detect individual raindrops and light around them. The system takes about 13 milliseconds to find raindrops and respond accordingly, so the top portion of the light beam would still hit the raindrops like a standard headlight. As it stands today, the system also works best at a speed of about 19 mph, where it’s 68.9 percent accurate at blacking out raindrops while still keeping over 95 percent light throughput. Drive faster and the system steadily loses accuracy.

As we always say with futuristic tech like this, it’s going to be many years until we see something commercially viable that works like this. The system will need some big improvements in digital light processing projector technology to work better, which is nothing to say of the fact that the whole package needs to get smaller for automotive packaging.

Still, the idea of going from halogen bulbs to xenon to LED to DLP projector headlights is intriguing, and having two DLP projectors and two wide-angle cameras mounted to the front of your car would open up a whole new world of active headlights that could shift to avoid blinding oncoming traffic or pedestrians.

Check out the research and let us know what you think.

Source: Carnegie Mellon University