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High-Tech Microphone Picks Voices From a Crowd
JerryQ writes with news of an impressive audio detection system from a company called Squarehead that was demonstrated during a professional basketball game. According to Wired, "325 microphones sit in a carbon-fiber disk above the stadium, and a wide-angle camera looks down on the scene from the center of this disk. All the operator has to do is pinpoint a spot on the court or field using the screen, and the Audioscope works out how far that spot is from each of the mics, corrects for delay and then synchronizes the audio from all 315 of them. The result is a microphone that can pick out the pop of a bubblegum bubble in the middle of a basketball game..."
...is it 315 or 325? Sheesh.
...'tis easier to blame than to improve.
Surely that would be better written as "terrifying" rather than "impressive"
Score:-1, Funny
In fact, that's exactly what TFA says.
You do not have a moral or legal right to do absolutely anything you want.
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I once took an excursion to Reddit, and later HN. Unlimited up/down voting sucks when dealing with a hive-mind.
Wow... why limit it to just stadiums? You could have arrays of these things lining every street and every mall! Just imagine how many terrorists you could catch by processing all the millions/billions of conversations going on in public places. All that data would be handy for collecting evidence against criminals too, you just go back through your chatlogs (all indexed per-person with voice/facial recognition) and dig up every conversation they've ever had outside.
It occurs to me that if you store all 325 audio streams with accurate time-codes and the relative positions of the microphones you would be able to do this at any time later on the stored sound as well. You could probably get away with much fewer than 325 microphones at some cost in quality.
Yes. And that's already part of the system.
I read the article. It went from 325 to 315 to 300. They may have gotten it down to a single mic had they kept writing.
Maybe I should've read it then.
But I, like most Slashdotters, am so quick that I can just glance at a poorly written summary and instantly understand all that needs to be known about the topic. It's really a wonderful time-saver being so damn smart I don't even need to know the facts.
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This sounds like beamforming. Submarines do this. Works great.
This system might also be hackable, such that people can preserve their privacy and not be listened in on from hundreds of feet away.
You simply have a microphone near your mouth, sample it, and repeat the sound out of a speaker with slight echoes with randomised delays. There must be something that could interfere with the process they use to "zoom in" on a particular sound source. Maybe if you can measure the distance to the listening device, it would be possible to manipulate the frequency of sounds you are making so as to create a standing wave or something that would cause the microphones to be overloaded or to hear nothing..... shit, maybe the tech that drives noise cancelling headphones could be used here? Who you are speaking to gets an earpiece with unedited sound piped to them, and speakers on your lapels kick out anti-sound so eavesdroppers hear nothing.
So now in public, you just need to have strings of randomised flashing IR LEDs illuminating your face, so CCTV has a hard time capturing your image, and now something to mess with your voice so that The Man cannot listen in too! If you are thinking "paranoid fucker", I am thinking what the fuck business is it of people to listen in on me? And that's a rhetorical question: I don't need to be told to think of the children, etc..
Car analogies break down.
This is a cool application of a well used technique. http://en.wikipedia.org/wiki/Phased_array
Just like Congress!
And, to be back on topic, referees.
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My father, would tell me stories when I was growing up about helping design a surveillance tool for ease-dropping on restaurant conversions that used the same principle. They had a map of the table layouts and you would place a pointer over the table you wanted to listen to. Mics hidden around the edge of the restaurant would capture the sound. This was back during the early 60's so they used a mechanical delay mechanism. Said it worked as well as if you had planted the mic at the table, plus you didn't have to worry about where they sat. Like many things, this is more powerful and versatile but hardly anything new.
... to a political rally near you. You probably don't need particularly accurate microphone placement and, in fact, if you had precise position and velocity coordinates of each of the mikes at any given time, they could even be moving.
That is all.
Just in case anybody is confused, that is cool as shit. That's all.
This is the classic phase array antenna approach from radar tech applied to sound. Cool application though.
In fact it is easier for sound because the amount of data per element is much smaller than in let's say a radar.
Baker's Law: Misery no longer loves company. Nowadays it insists on it
http://www.sigsegv.cx/
no, but it can focus entirely on one vuvuzela
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He'd kill us if he had the chance.
--- The American Way of Life is not a birthright. Hell, it's not even sustainable.
Meme-mongers: Imagine a Beowulf cluster of that array! Meta-commentators: (Present company excluded, well not really) Timothy! MAFIAACS: Oh great, they just copyrighted my gum-popping sounds. Insightful curmudgeons: Given sufficient sensitivity, this could be done with a tetrahedral array--50 years. Now, get off my lawn!
Yeah, but does it run Linux?
The higher the technology, the sharper that two-edged sword.
Yes, to point out that a thing's technical impressiveness need not preclude its creation of terror.
That's fine, but you're comparing a device whose purpose is to capture audio with a device whose purpose is to cause as much destruction as possible.
Recording every voice in the crowd has significant implications for society. Some people will find those implications terrifying--especially people who distrust society because they have been intellectually threatening to often-foolish authority figures for much of their lives. Such people happen to hang out on slashdot.
This is just a microphone array. If a government is going to conduct surveillance on its people without a warrant, it doesn't really matter what device they use to do that. That capability already exists. If a government is doing that, the answer is to get the government to stop doing that, not limit your technical progress.
Do you think the people who build this are the first to think of or build it? Are these people giving the nefarious government a tool that they don't already have? Local governments in the US have been using audio triangulation to pinpoint the source of gunfire in a city for a long time, this is very similar. Instead of identifying the unknown location, you're targeting the known location.
http://en.wikipedia.org/wiki/Gunshot_Location_Detection_System
That was inspired by seismology, which has been going on for even longer.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
I do some community theater work as a hobby - amateur stuff - and wonder if something like this could be used to track multiple actors on stage? Might be better than fitting them all with transmitters and lavaliers. Targeting would become the next problem, I guess.