Future is bright for smart headlights

• Reprints

Driving in a driving rainstorm is one of the scariest events motorists face. It’s especially dangerous when windshield wipers cannot keep up with the pace of the rain, even when wiping at the highest speed setting.

And believe it or not, even expensive luxury cars with the newest and best features, including high-illumination headlights, are not immune to this problem. Some rainfall is so heavy that seeking shelter off the road is the best way to cope with such storms.

Engineers are constantly working to solve this problem for drivers. One of the latest efforts is under way at Carnegie Mellon University in Pittsburgh, Pa., where a team of researchers has developed “smart headlights” that shine between raindrops to improve visibility at night.

The system employs a high-speed camera to predict within milliseconds where raindrops will fall and then deactivates light beams that otherwise would bounce off the precipitation and impair visibility.

“If you’re driving in a thunderstorm, the smart headlights will make it seem like it’s a drizzle,” said Srinivasa Narasimhan, associate professor of robotics. “A human eye will not be able to see that flicker of the headlights. And because the precipitation particles aren’t being illuminated, the driver won’t see the rain or snow either.”

Narasimhan said the researchers analyzed rain with high-speed cameras and determined precipitation is made up of discrete drops with lots of space between them. They then created a smart system that effectively distributes light between the raindrops.

Conducting tests with a weather chamber in their lab, the researchers were able to adjust headlight illumination in a mere 13 milliseconds. That’s good enough to effectively eliminate between 70 to 80 percent of visible rain in a heavy storm with only a 5 or 6 percent loss of light.

Narasimhan said the team will need to cut the system’s response time to just a couple of milliseconds to be effective in snow and hail at highway speeds and is confident of the feasibility of accomplishing that.

The Carnegie Mellon apparatus uses a camera with an off-the-shelf DLP projector. A university spokesman said the researchers believe they will have a prototype system capable of being mounted in a vehicle for testing in three years. The smart headlight system never will eliminate all precipitation from the driver’s field of view, the researchers admitted, but they claim it can reduce reflection and distortion and minimize distraction. Narasimhan’s team is now engineering a more compact version of the smart headlight that in coming years could be installed in a car for road testing.

A bonus benefit is that the system can detect oncoming cars and direct the headlight beams away from the eyes of those drivers. That would eliminate the need to switch from high to low beams.

“One good thing is that the [smart headlight] system will not fail in a catastrophic way,” Narasimhan said. “If it fails, it is just a normal headlight.”

Carnegie Mellon said the research is receiving funding support from the Office of Naval Research, National Science Foundation, Samsung Advanced Institute of Technology and Intel. Other professional research collaborators include Takeo Kanade, professor of computer science and robotics, and Anthony Rowe, assistant research professor of electrical and computer engineering.