We are talking about a prototype headlight system that can detect raindrops and snow-streaks and still manage to increase the visibility on the road. It ‘dis-illuminates’ them and does the task of increasing visibility. In this system, a digital projector illuminates the raindrops for several milliseconds and you can see this via a camera that is mounted on its side capturing the location of each raindrop.
The system’s software has been built to predict the location of these raindrops enabling to know the driver’s field of view. Now when a headlight is turned on, the normal light rays that would hit the raindrops are automatically shut down. This reduces the glare and leaves only those beams of light which would anyways travel uninterrupted in between the falling drops to lighten up.
The operating range of this projector is about three to four meters which is called the critical range. According to tests conducted using a Toyota Prius, at this range the glare is considered to be the most distracting to the eyes of the driver. This system has been developed by Carnegie Mellon computer science professor Srinivasa Narasimhan with several others. These findings were presented at Microsoft Research at the Research@Intel 2012 by him.
All researchers have put together different car speeds and rainfall intensity in the laboratory by changing speed at which rain drops fall to be doubly sure. Actual water propagation was used to fall before the projector to test it. It has been seen that the rain drops can invariably be made invisible at low speeds while increasing the visibility at higher speeds by dimming the existence of the rain drops itself.
Imagine that in severe thunderstorm rain, the accuracy is 70 percent at 30 kilometers per hour and 15 to 20 percent at 100 kilometers an hour; so this amount of rain is anyways removed from the view. Just by dimming the headlights by a few percent, you can filter the rain.
It’s being understood that a bigger and better camera could improve the system but it would also mean a costlier headlight system. Now whether this prototype could actually work in real-life is another matter of contention.