I tried fooling the system by letting the car drift right with the left turn signal on.
"Think of it as a virtual rumble strip." That's how Jack Johnson, president and CEO of Iteris, described to me the company's Lane Departure Warning (LDW) system now available on the Infiniti M. I was among a group of auto journalists who tried out the technology last week in Boston on a rainy afternoon.
The system, developed with Tier One supplier Valeo, uses a CMOS camera mounted behind the top of the windshield and a "PDA-level" processor crunching 30 frames/sec to detect lane markings out to 30 meters. Above 45 mph (where most accidents occur), if the car is leaving its lane without the turn signal on, the driver is alerted with a series of warning chimes and an indicator light. I tried fooling the system by letting the car drift right with the left turn signal onbut a warning correctly was given. Eventually, I can see motorists using repeated activation of the system as a sign to pull off and get some rest.
While the system will not operate if it can't detect markings, Iteris engineers spent ten years acquiring reams of imaging data under various lighting and weather conditions to maximize LDW operational range. Basically, if markings were tough for humans to see they were difficult to discern with image processing.
But proprietary algorithms the engineers developed are key to system utility. As an example, in what little Iteris would reveal, Automotive Sensors VP Francis Memole told me that the CMOS imager is fairly conventional (and thus low cost) with a dynamic range of roughly 60-65 dBbut "software control" of image processing significantly expands those numbers to be useful. He adds the developers "didn't know what they couldn't do [mathematically]," but were able to "code with common sense" in realizing a workable but high dynamic range system.
Iteris LDW has been available on commercial trucks in both the U.S. and Europe for three and four years, respectively. Teaming with Valeo brought it into the passenger car market. Iteris says about 15,000 trucks are equipped with the system and that a survey of truckers found 70% feel the system makes them better drivers.
But how significant is LDW to the average driver? Depending on whose numbers are used, between 30 and 50% of fatal accidents are caused by vehicles departing their lane or the road. The National Highway Traffic Safety Administration notes a drop in fatalities of about 50% on highways where grooved pavement rumble strips have been added. This projects out to roughly 9,000 lives in the U.S. saved annually if virtual rumble strips, that is LDW, were available in all vehicles. That's pretty significant, I think, given the increasing distractions drivers face today.
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