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How To: Be Invisible

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If you have several billion dollars and
a defense department contract:

You may be able to get invisible thanks to a new technology based off the Fantastic Four. According to comic book mythology, the Invisible Woman pulls off her shtick by bending light waves around her body with a force field—so instead of seeing a blond chick in spandex, super villains see whatever happens to be behind her. So far, this skill is strictly for fictional hotties, but researchers at St. Andrews University in Scotland think that, in the near future, those of us not genetically altered by radioactive rays from space may be able to do something similar. The concept works like this: We see objects because they reflect light back to our eyes. So if an object were able to curve light around itself like water flowing around a river stone, it would be effectively invisible. We'd see all the things around and behind it that reflected the light instead. To be invisible, a person or object would have to be concealed behind a shield made of metamaterials, highly engineered manmade solids that can bend waves of energy. So far, the metamaterials are still theoretical, but scientists agree that they're coming soon. Both the researchers at St. Andrews and a different group at the Pentagon have predicted that successful metamaterials capable of hiding objects from radar or electromagnetic waves (though, sadly, not from the human eye) could debut as early as 2008.

If you have a couple million and airfare to Japan:
You can be transparent right now, though people may accuse you of cheating. Tachi Laboratories at the University of Tokyo has developed a sort of virtual invisibility cloak made of a luminescent material, similar to a movie screen or stop sign paint. Using a digital camera linked to a powerful computer, researchers can project live images and video from behind the cloak onto its front, making it blend in, chameleon style, with the background. The effect isn't all that realistic; you won't be using this cloak to walk into a bank and rob it undetected. However, the technology promises to be very useful to surgeons, who could use it to "see" through their own hands for a better view of their patient's innards.

If you're on a budget:
You can't be invisible, but your Pyrex® glassware can. Turns out, Pyrex® and Wesson oil reflect light at almost the exact same angle—so if you immerse a rod of Pyrex® in a jar of cooking oil, the submerged glass will appear to vanish.

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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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