Hopping over a sidewalk pothole is so automatic you probably don’t notice you’re doing it. If you’re blind, it’s another story. And up until now even high-tech detector gadgets haven’t been able to help. Detectors just don’t do well with holes, and if those holes are small—the kinds of divots or depressions that can easily send a person stumbling but don’t look like much—then the technology is even less capable of spotting them.
Enter electrical engineer Elaine Wong’s smart detector, a combination of cameras, lasers and machine learning methods which can spot toe-catching potholes early enough to stop a fall. In limited testing, Wong’s detector has successfully identified potholes 95% of the time.
The device uses a very simple principle. The lasers project a grid on the ground ahead, and the cameras measure how much light comes back. If a surface is completely flat, then the light reflected back will be equally uniform. But if there is a hole, then the laser light will have to travel a little further to get back to the camera, and will therefore be ever so slightly dimmer. The detector (a repurposed GoPro camera) is sensitive enough to spot this and a connected computer interprets the readings and decides if it’s seeing a hole. If it spies one, it sounds a warning, “Pothole detected.”
“There’s nothing in existence that we know of that detects non-protruding hazards,” Wong told IEEE Spectrum. Her device is designed to be fitted to a walking frame or a wheelchair, scanning the way ahead as it goes, but in future it could be wearable. “You want it to be fast, you want it to be small, you want it to be low complexity,” she said.
One might wonder, though, what’s wrong with a stick? A white stick with a plastic ball on the end, designed to be swept across the pavement ahead, not only detects “non-protruding hazards” (aka holes), but never runs out of batteries, never malfunctions, and never squawks “Pothole detected!” at you every time it spots an obstacle. It even works with protruding hazards, like curbs, or feet, or stair steps. But Wong’s device has one advantage over the tried-and trusted stick: It’s hands-free, which could make quite a difference for some users.
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