‘Smart’ Headlights Could Make Roads Safer
Thanks to research by a team at Carnegie Mellon University’s Robotics Institute, drivers will one day be able to see better when driving at night in rainstorms and snowstorms, which could prevent many accidents. The team, led by Srinivasa G. Narasimhan, associate professor of Robotics, has created a “smart headlight” system that continuously redirects light to shine between the raindrops.
As Nancy Owano writes for Phys.org, typically in low-light conditions, to see the road, drivers rely mostly on headlights, but those same headlights reduce visibility when their light is reﬂected off the drops of precipitation back to the driver. Standard headlights make raindrops and snowflakes appear as bright flickering streaks.
Or, as Christopher MacManus puts it for CNET’s Crave (a blog about “gorgeous gadgets and other crave-worthy stuff”): “Driving around in a snowstorm or heavy rain often feels similar to the hyperspace travel effect seen in the various ‘Star Wars’ movies, which can distract even the most seasoned driver (unless you can make the Kessel Run in 12 parsecs).”
But, unlike humans, high-speed cameras see precipitation as “sparsely spaced, discrete drops,” which, Narasimhan said, leaves plenty of space between the drops for light to be distributed, as long as the system can respond rapidly, McManus reports.
As Owano writes, the prototype smart headlights work so that the lights shine around, rather than on, the drops. “If you’re driving in a thunderstorm, the smart headlights will make it seem like it’s a drizzle,” Narasimhan said in a Carnegie Mellon press release.
MacManus writes that the smart headlights contain an imaging system comprised of a projector, a camera, and a light beam splitter. Here’s how the Carnegie Mellon press release explains the system:
The 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.’
The entire detection and shading process, MacManus writes, takes only 13 milliseconds. According to the Carnegie Mellon press release, at low speeds, the smart headlights system could eliminate 70 to 80 percent of visible rain during a heavy storm, losing only 5 or 6 percent of the light coming from the smart lights. The press release suggests the system might not cost a lot:
To operate at highway speeds and to work effectively in snow and hail, the system’s response will need to be reduced to just a few milliseconds, Narasimhan said. The lab tests have demonstrated the feasibility of the system, however, and the researchers are confident that the speed of the system can be boosted.
Road-worthy systems likely would be based on arrays of light-emitting diode (LED) light sources in which individual elements could be turned on or off, depending on the location of raindrops. New LED technology could make it possible to combine LED light sources with image sensors on a single chip, enabling high-speed operation at low cost.
As McManus writes, Narasimhan said in a presentation that “wind, turbulence, and vibrations” from high speed can interfere with the performance of the smart headlights. But he said his team — consisting of Raoul de Charette, Robert Tamburo, Peter Barnum, Anthony Rowe, and Takeo Kanade — is at work on making a more compact smart headlight.