Sun July 28, 2013
'Batman' Style: How We Can See With Sound, Too
Originally published on Mon July 29, 2013 9:30 am
Birds do it. Bats do it. Now even educated people do it. Echolocation is the process used by certain animals to identify what lies ahead of them, by emitting sounds that bounce off objects.
Now a team of researchers has created an algorithm that could give the rest of us a chance to see with sound.
Lead study author Ivan Dokmanic of the Ecole Polytechnique Federale in Switzerland says the project started with a question: "Is it possible to just produce a sound and be like Batman or just hear the shape of the room?"
Dokmanic and his team made it happen.
First, they set up a few microphones around a room. Then, "hook these microphones up to an amplifier and a computer, produce some sound, and then just calculate the shape of the room based on the echoes that you receive from the walls in the room," Dokmanic says.
So what's it good for?
For starters, it could be used in architectural acoustics. Say you're building a concert hall and you know just how you want it to sound, Dokmanic says. "Just plug this into our algorithm. And then this algorithm will produce the room that produces these echoes," he says.
The technology could also be used as an aid for blind people. Dokmanic says it could "give some kind of optic feedback maybe to the user saying, 'OK, the general form of the room is like this,' or, 'There are obstacles here and there.' "
It could also be used in audio forensics. A recording that captured the sound of a crime being committed could then be used to reconstruct the room, providing evidence to investigators.
But these applications are not available just yet. Dokmanic says he and his team are in the process of raising funds to expand the technology and hope to turn it into a smartphone app.
"I hope not too long — but the realistic horizon is two years to get something that's really usable by everyone," he says.
JACKI LYDEN, HOST:
Now, from sound beneath the waves to sound above ground. Birds do it. Bats do it. Now, even educated people do it. We're talking about echolocation: the process whereby animals emit sounds to locate objects. A team of researchers has created an algorithm that lets us see with sound. Ivan Dokmanic of the Ecole Polytechnique Federale in Switzerland says the project kicked off with a question.
IVAN DOKMANIC: Is it possible to just produce a sound and be like Batman or just hear the shape of the room, right, just like "Dark Knight" style?
(SOUNDBITE OF MOVIE, "THE DARK KNIGHT")
MORGAN FREEMAN: (as Lucius Fox) You've turned every cellphone in Gotham into a microphone.
CHRISTIAN BALE: (as Batman) And a high-frequency generator-receiver.
LYDEN: Only Dokmanic's technology uses microphones in a different way. First, you set up a few of them around the room.
DOKMANIC: Hook these microphones up to an amplifier and to computer, produce some sound, and then just calculate the shape of the room based on the echoes that you receive from the walls in the room. Times when these echoes arrive enable us, using some mathematical tools, to determine where the walls actually are.
LYDEN: So how could we actually apply this technology in the real world? Well, for one thing, let's say you're building a concert hall and you know exactly what kind of sound you want.
DOKMANIC: In architectural acoustics, you could really say, okay, this is how I want my room to sound. And then just plug this into our algorithm, and then this algorithm will produce the room that produces these echoes.
LYDEN: Or the technology could be used as an aid for the blind providing optic feedback.
DOKMANIC: Saying, okay, you know, the general form of the room is like this, or there are obstacles here and there, and you know, be careful.
LYDEN: It could also come in handy when solving a crime if there happens to be a recording of it.
DOKMANIC: You can imagine that you could actually reconstruct the room where the sound was recorded.
LYDEN: But these applications aren't available for the public just yet. As to when we might see them, Ivan Dokmanic is optimistic but realistic.
DOKMANIC: I hope not too long. But, I guess, the realistic horizon is maybe two years to get something that's really usable by everyone.
LYDEN: Dokmanic says he and his team are raising funds to expand the technology. They hope to turn it into an app coming soon to a smart phone screen near you.
(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.