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Federal Aviation Administration

What Pilots See When You Shine a Laser Pointer at Aircraft

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Federal Aviation Administration

Michael Brandon Smith was standing in his driveway one afternoon, beer in one hand and laser pointer in the other. Bored, he decided to see if the pocket-sized novelty could reach the helicopter passing overhead.

It could. He knew because a short time later, police were knocking on Smith’s door. Not long after that, Smith was sentenced to two months of house arrest and two years’ probation. The helicopter was a St. Louis police transport responding to a burglary call; it had to divert when the laser pointer temporarily disoriented its occupants.

Ever since laser pointers were introduced as a cheap, consumer-use trinket in the 1990s, there’s been a human tendency to point them at things: other people, animals, and, more recently, aircraft. While driving Mr. Mittens to exhaustion with a dot can be fun, the latter is a federal offense and quite possibly the lamest explanation you could ever give to another inmate.

On the ground, laser pointers appear to have a weak, diluted projection. That’s because general consumer-use pointers are not allowed to exceed 5 milliwatts (mW). But people tend to underestimate just how far the light can be thrown, or what happens to it once it settles on a passing airplane or helicopter. The FBI arranged for a video to demonstrate:

FBI

That "weak” light originating from the ground not only reaches the cockpit of planes, it’s also magnified considerably by their Plexiglas windows. The pilot’s field of vision is compromised as the light comes in bursts, a strobe effect the FBI has compared to setting off a camera flash in a dark room. At distances of up to 1200 feet, it can engulf a cockpit. It remains a distraction hazard all the way up to 12,000 feet.

While the practice has yet to result in an accident, pilots have been forced to change course; more than 35 have required medical attention, which is why both the Federal Aviation Administration (FAA) and the FBI have taken extraordinary measures to try and dissuade people from pointing them at planes—a bizarre habit officials have called “lasing” that resulted in nearly 4000 reported cases in 2013 alone.

Smith was using a consumer-grade pointer; the FBI looks unkindly towards anyone using a commercial model. (Though legal to own, they’re not intended to be marketed as “pointers.”) In 2012, 19-year-old Adam Gardenhire received 30 months in federal prison for distracting pilots with a powerful laser. That same year, Sergio Rodriguez was arrested for the same crime, using a device 13 times more potent than the norm. He got 14 years.

What motivates people to do this is somewhat of a mystery. The FBI solicited comment from perpetrator Jason Stouder, who told them that he was just “admiring” the laser. He wanted to see “how far it goes and what it hit. The helicopter flew by and I made the decision to see if it would reach the helicopter. Obviously it did. But, in viewing the video I had no idea it illuminated the whole cockpit and blinded everybody inside.”

While it can be difficult to isolate a pointer's whereabouts, GPS tracking in helicopters can usually narrow down a location, as in the cases of Stouder and Smith. (If someone is pointing it at planes, officials can dispatch a helicopter to see if they can get a “hit” from the attacker.)

Some lawmakers want to see pointers greater than 5 mW banned outright. Charles Schumer, U.S Senator from New York, called for their prohibition after four planes at La Guardia were targeted last May.

That probably wouldn’t go over well with laser enthusiasts who use units up to 1000 mW (1 watt) for science experiments. In New South Wales, Australia, where pointers above 1 mW have been banned since 2008, a black market has cropped up, potentially making the situation worse: high-powered lasers are being imported and sold as low-watt units.

Because pinpointing offenders can be difficult, the FBI offers a $10,000 reward for information leading to a laser-related arrest.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Name the Author Based on the Character
May 23, 2017
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