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How to eavesdrop from a distance

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Another lesson from The Action Hero's Handbook, which this time is also pretty useful for your everyday nosey neighbor, jealous ex-lover, private eye or other such non-heroic profession. Let's get started!

1. Determine the topic of conversation beforehand.
Kind of a no-brainer, yeah, but it'll certainly help to know whether you're spying on drug dealers, contract killers or suburban moms gone wrong. In any case, knowing the topic will help limit the vocabulary used.

2. Position yourself in front of or to the side of the speaker
If you're better at tongue-reading, position yourself slightly to the side. If lips are your specialty, you'll want a frontal view.

3. Stay mobile
You may need to reposition yourself during the conversation as the speakers move their heads from side to side and shift their bodies. But be smart -- a Segway is great for mobility, but not so great as far as the whole "incognito" thing goes.

4. Read consonant sounds using the following basic criteria
"¢ P, B and M are formed with both lips together.
"¢ F and V are formed with the top teeth on the bottom lip.
"¢ Sh, Ch, J, Y and Zh are formed with the lips in a large pucker.
"¢ Th sends the tip of the tongue sticking out through the teeth.
"¢ S (C) and Z (X) are formed by the lips making a smile.
"¢ R is formed by the lips making a small pucker.
"¢ W is formed by the lips making a closed pucker.
"¢ K (hard C, Q), G (hard) and H are formed with an open (neutral) mouth and are never perceptible. Experience and context will help you discern them.
"¢ T, D, N and L are formed with the tip of the tongue moving up to the top of the mouth and then down (seldom perceptible -- again, context and practice help).

5. Multiply your exposures
Use a team of readers in multiple locations to get the whole story. Station the readers in various proximities to the speaker(s). Each reader will obtain a different part of the conversation. And if you fail, at least the speakers will feel weird, wondering why a roomful of people are all staring at them.

Of course, this is just the beginning. Eavesdropping is a learn-by-doing kind of activity, so get out there and start minding other people's business!

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iStock // Ekaterina Minaeva
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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