Published on July 12th, 2012 | by James Ayre2
Smart Headlight System Sees Through the Rain
July 12th, 2012 by James Ayre
Driving during a rain or snowstorm can be can be a struggle at night, but a newly developed ‘smart’ headlight system will make it much easier. The system greatly improves visibility by continually redirecting light to shine between particles of precipitation.
The system was created by researchers from Carnegie Mellon University’s Robotics Institute.
Demonstrated in laboratory tests, the system prevents the distracting and dangerous glare that precipitating precipitation creates when it reflects headlight beams back at the driver.
“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 camera tracks the motion of the raindrops or snowflakes, and then a computer algorithm is applied to the data to predict where the particles will be just a few milliseconds later. The light projection system then adjusts itself, deactivating the light beams that would 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 human eyes, rain usually appears as streaks moving through the air, but to high-speed cameras, they are widely spaced, discrete drops. Between them, there remains plenty of space where light can be distributed.
“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 13 milliseconds. At low speeds, such a system could eliminate 70 to 80 percent of visible rain during a heavy storm, while losing only 5 or 6 percent of the light from the headlamp.”
In order for operation at highway speeds and for good function in snow and hail, the response time of the system will need to be reduced to just a few milliseconds. Lab tests have shown that the system is certainly feasible, and researchers are very confident that the speed of the system can be improved.
As an example, the test apparatus is a joined camera and off-the-shelf DLP projector. Future systems would likely “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.”
Advancements in LED technology may make it possible to combine LED light sources and image sensors onto a single chip. This would allow very high-speed operation at a low cost.
The researchers are now working on a more compact version of the prototype that can be installed in a car for road testing.
Another advantage of the system is that it can detect oncoming cars and move the headlight beams away from the eyes of those drivers, that would eliminate the need to shift from high to low beams.
“One good thing is that the system will not fail in a catastrophic way,” Narasimhan said. “If it fails, it is just a normal headlight.”
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