A new smart headlight system could help drivers to see during a rain or snowstorm. Developed by US researchers at Carnegie Mellon University (CMU), the system improves visibility by constantly redirecting light to shine between particles of precipitation. ‘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 at CMU. When headlight beams are reflected by precipitation back toward the driver it can create distracting and sometimes dangerous glare. The new system uses a camera to track the motion of raindrops and snowflakes, and then applies a computer algorithm to predict where those particles will be just a few milliseconds later. The light projection system then adjusts to deactivate light beams that would otherwise illuminate the particles in their predicted positions. ‘A human eye will not be able to see that flicker of the headlights,’ Narasimhan said. ‘And because the precipitation particles aren’t being illuminated, the driver won’t see the rain or snow either.’ To people, rain can appear as elongated streaks that seem to fill the air. To high-speed cameras, however, rain consists of sparsely spaced, discrete drops. That leaves plenty of space between the drops where light can be effectively distributed if the system can respond rapidly, Narasimhan explained. In their lab tests, Narasimhan and his research team demonstrated that their system could detect raindrops, predict their movement and adjust a light projector accordingly in 13ms. At low speeds, such a system could eliminate 70 to 80 per cent of visible rain during a heavy storm, while losing only five or six per cent of the light from the headlamp. 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.