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Portland Nights -- a City in Time Lapse

Continuing my week of excellent HD videos, here's an HD time lapse from my hometown of Portland, Oregon. The time lapse is kinetic, the camera always moving, and it shows scenes from sundown to sunrise in Portland, as winter approaches. It's beautiful, detailed, and well-edited. My favorite part is when airplanes zip by at dramatic moments (this is most apparent if you watch at 1080p fullscreen). The best part? The first and last sequences actually use HDR photography to achieve an extremely colorful look -- read more about the making of the video for more interesting trivia.

Photography and editing by Lance Page; music by Andrew Parish. Enjoy:

Here's a snippet from Page's blog post explaining the video, concerning the (mild) dangers of shooting time lapse in an urban setting:

I stirred up a bit of suspicion while getting the two parking structure roof top shots. The reason being I was literally hanging half of the six foot track off the edge of the building with the cart and camera slowly creeping out to the end as the shot progressed. The first one wasn’t too bad, right before I started the shot I was told by a security guard that I had to leave and after about five minutes of begging and pleading he finally told me I had an hour and he’d be back. So that was that, then a couple nights later I had another shot set up on the top of another parking structure and maybe two thirds of the way through the shot I noticed a bright light shining up at my camera. I looked down and saw a cop car blasting its flood light up at me. Then after the time it takes to drive in a circle 8 times there were two squad cars at the top of the building approaching me. I was spooked, thought I was really in for it. The first officer got out, asked me to take my hands out of my pockets and asked me what I’m doing. When I told him he then told his fellow officer “he’s just getting a time-lapse” and they got back in their squad cars and drove off. In the shot you can see the flashing brightness of the flood light and then the brief light from their headlights on the top of the building.

(Via The Portland Mercury.)

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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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