Smart headlights let drivers see between the raindrops

Smart headlights let drivers see between the raindrops

(Phys.org) -- A Carnegie Mellon professor and his team have developed a prototype headlight system, or “smart headlights” designed to help you make your way safely home if driving through a downpour or snowstorm where visibility is threatened. During low-light conditions, drivers rely mainly on headlights to see the road but the same headlights reduce visibility when light is reflected off of precipitation back to the driver. The prototype smart headlights work in such a way so that lights help, not hinder, the stressed-out driver.

In difficult weather conditions, headlights make and snowflakes appear as bright flickering streaks. The university team sought to “dis-illuminate” the distracting lights. The headlight beams shine around rather than on the drops. The headlights are in turn enabling the driver to see though the rain and snow and avoid the distressing glare that goes with standard headlights.

Smart headlights let drivers see between the raindrops

Computer science professor Srinivasa Narasimhan, whose research focuses on computer vision and computer graphics at Carnegie Mellon, wanted to see if he and his team could stream light in between the drops. Their answer consists of a co-located imaging and illumination system-- camera, projector, and beamsplitter. The idea of the design is to integrate an imager and processing unit with a light source. The beamsplitter (50/50) permits optically co-locating the camera and projector to eliminate the need for stereo reconstruction, according to team site comments about the project, reducing computations and increasing system speed.

The camera images the precipitation at the top of the field of view. The processor can tell where the drops are headed and sends a signal to the headlights, which make their adjustments and react to dis-illuminate the particles. The entire action, starting from capture to reaction, takes about 13 ms. (The system runs at 120 Hz. The camera uses a 5 ms exposure time and the system has a total latency of 13 ms.)

One question central to their efforts is how fast will the system need to be, to be actually effective, in a car. “Computer simulations show that a system operating near 1,000 Hz, with a total system latency of 1.5 ms, and exposure time of 1 ms can achieve 96.8% accuracy with 90% light throughput during a heavy rainstorm [25 mm/hr] on a vehicle traveling 30 km/hr. However, 400 Hz with less accuracy will be a significant [>= 70%] improvement for the driver,” according to the researchers.

The system's operating range is about 13 feet in front of the headlights. In the paper, “Fast Reactive Illumination Through Rain and Snow,” the authors Raoul de Charette, Robert Tamburo, Peter Barnum, Anthony Rowe, Takeo Kanade and Srinivasa G. Narasimhan, wrote, “In contrast to recent computer vision methods that digitally remove rain and snow streaks from captured images, we present a system that will directly improve driver visibility by controlling illumination in response to detected precipitation. The motion of precipitation is tracked and only the space around particles is illuminated using fast dynamic control.”

Smart headlights let drivers see between the raindrops

The team used a physics-based simulator to evaluate how their system would perform under a variety of weather conditions. Their simulation results show that it is possible to maintain light throughput well above 90 percent for various precipitation types and intensities. Then they demonstrated a proof-of-concept prototype system operating at 120Hz on laboratory-generated rain, which validated their earlier simulations.

Equipment used in the prototype consists of a camera with gigabit ethernet interface (Point Grey, Flea3), DLP projector (Viewsonic, PJD62531), and desktop computer with Intel architecture (Intel i7 quad core processor).

The team's next steps will involve making the system faster and more compact to test on a moving platform. They said the technology under research for those ends may take three to four more years and “commercializing it as a product will take additional years.”

Because the prototype was built with off-the-shelf components, data transfer speed is slower than if the components were more closely integrated. Developing specialized hardware that more closely integrates the camera and projector with a processing unit will bring improvements. They also said more sophisticated algorithms are needed to maximize speed and account for factors such as vehicle motion and wind turbulence.

Carnegie Mellon’s Prof. Narasimhan presented the findings this year at Microsoft Research and at Research@Intel 2012.

ICCP 2012

Explore further

A Multi-Layered Display with Water Drops (w/ Video)

More information: "Fast Reactive Control for Illumination through Rain and Snow" Raoul de Charette, Robert Tamburo, Peter Barnum, Anthony Rowe, Takeo Kanade and Srinivasa G. Narasimhan, Proceedings of IEEE Conference on Computational Photography (ICCP), 2012.

www.cs.cmu.edu/~ILIM/projects/IL/smartHeadlight/

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Citation: Smart headlights let drivers see between the raindrops (2012, July 4) retrieved 18 July 2019 from https://phys.org/news/2012-07-smart-headlights-drivers-raindrops.html
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Jul 04, 2012
These guys are smart yet so so stupid. So.. it enables you to drive your car faster in the rain right? Consider this scenario, a pedestrian or other driver needs to cross the street and it's raining pretty hard.. they look left they look right..(then left again) and start to cross then wham they are hit by one of these cars with the "improved" headlights installed. Of course they were hit because the driver was going faster because they could see. (but others could not)Huge liability issues.

Jul 04, 2012
they look left they look right..(then left again) and start to cross then wham they are hit by one of these cars with the "improved" headlights installed.

What you're saying here is that "everybody should be equally blind and the degree of blindness should be determined by the most blind person on the road". I don't think that's sensible.

So.. it enables you to drive your car faster in the rain right?

I think you've never driven through a downpour or snowstorm. In such a situation visibility is not the limitig factor to your speed (safety and grip are).

Jul 04, 2012
apparently that person doesn't drive. ever try to see the lane markers when driving 15 MPH in a downpour? This technology is for that reason, not to allow you to drive faster. think next time before looking like a fool.

Jul 04, 2012
"So.. it enables you to drive your car faster in the rain right?"

Sorry, but that's psychopathy at its finest...

Jul 04, 2012
they look left they look right..(then left again) and start to cross then wham they are hit by one of these cars with the "improved" headlights installed.

What you're saying here is that "everybody should be equally blind and the degree of blindness should be determined by the most blind person on the road". I don't think that's sensible.

So.. it enables you to drive your car faster in the rain right?

I think you've never driven through a downpour or snowstorm. In such a situation visibility is not the limitig factor to your speed (safety and grip are).


Visibiliy is part of safety..

Jul 04, 2012
"Of course they were hit because the driver was going faster because they could see."

I mean, this is just sheer stupidity. As if everyone drives really fast and dangerously when they can see properly, which is most of the time.

Jul 04, 2012
more sophisticated algorithms are needed to maximize system speed and account for factors such as vehicle motion and wind turbulence.


Well, good luck with that. Call us back when you're anywhere near making this practical. Then shut up and take my money.

Jul 04, 2012
they were hit because the driver was going faster because they could see. (but others could not)Huge liability issues.


Your argument is wrong. Following your reasoning we should remove one of the two headlights in order to reduce visibility, thus forcing drivers to go slower... absurd

Jul 04, 2012
Fascinating unintended consequences. Humans slow down for adverse conditions but will not when the conditions do not appear adverse for them. Will their and societies safety increase or decrease? Better lights have improved safety up to the point where oncoming drivers are blinded. Four wheel drivers overestimate stopping ability and have higher turnovers and collisions. Will the added cost and complexity result in lower cost for society? Cool idea, however, vet the obvious unintended consequences!

Jul 04, 2012
These headlights are awesome! Wonderful example of innovation.

Jul 04, 2012
One benefit would be while driving behind a transport truck in the rain, or when one passes you

Jul 05, 2012
mrlewish, how about, we remove the brakes, so car drivers feel weary going too fast...

I understand your point, there are always a few drivers who max out whenever they can, but they runover pedestrians in any wheathercondition. I think the bottomline is it could save more lives than it will cost...

Jul 05, 2012
I'm wondring if it wouldn't be better to filter via a liquid crystal layer on teh windshield rather than removing part of the light.

By blocking parts of the beam you're reducing light output. Some of that light is 'bad' (reflected by water droplets) but other parts of that light would have gone on to illuminate nearby areas.
In an extreme case the system in teh article would shut down most of your headlights. OK, one might argue that in such extreme cases one shouldnt be on the road, but nevertheless...

Jul 05, 2012
Yes, What about fog? It would shut down the lights altogether. Also, Reflectors on Vehicles, Bicycles, oncoming Headlights,etc. This system would also need a computer for pattern detection, which it would self negate, creating a catch 22.

Jul 05, 2012
Less light ahead is preferable to more light coming back to our eyes. Isn't that the point?

Jul 05, 2012
I'm wondring if it wouldn't be better to filter via a liquid crystal layer on teh windshield rather than removing part of the light.

By blocking parts of the beam you're reducing light output. Some of that light is 'bad' (reflected by water droplets) but other parts of that light would have gone on to illuminate nearby areas.
In an extreme case the system in teh article would shut down most of your headlights. OK, one might argue that in such extreme cases one shouldnt be on the road, but nevertheless...


I think editing the outgoing light is better than editing the incoming light. In an emergency; Editing the lights could make it difficult to see only at night. Editing the light coming through the windshield could make it difficult to see even during the day.

Jul 05, 2012
"So.. it enables you to drive your car faster in the rain right?"

Sorry, but that's psychopathy at its finest...
Naw it means your smart car will be able to drive itself faster in the rain.

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