Almost everyone has played the air guitar at some point or another. Now, computer scientists in Finland have turned this rock fantasy into a multimedia reality.
An air guitar that really rocks. I'm Bob Hirshon and this is Science Update.
(Audio: Air guitar clip)
This rendition of “Smoke on the Water” may not be brilliant, but it’s pretty good for an air guitar. The virtual guitar is the brainchild of computer scientist Aki Kanerva and his colleagues at the Helsinki University of Technology in Finland. To use it, you just slip on a pair of gloves and step in front of a camera.
And you take a rock guitarist pose, as if you were holding an imaginary guitar, and then just rock away.
The camera tracks the movement of one hand along the imaginary fret board and the strumming of the other. The information is sent to a computer that turns the gestures into riffs and licks. And while Eric Clapton’s job is probably safe, the system’s giving average Joes a chance to feel like rock gods. I'm Bob Hirshon, for AAAS, the science society.
Making Sense of the Research
Since the dawn of rock music, teenagers (and many adults) everywhere have been cranking up the stereo and playing air guitar along with their favorite bands. Now, Kanerva’s group has turned this tradition on its ear—by creating an air guitar that actually makes its own music.
Part of the magic of Kanerva’s air guitar is that the technology is almost completely invisible. The gloves that you wear are just ordinary orange gardening gloves. As you’re playing, a web camera, programmed to recognize only the color orange, watches your gloves and tracks their movements. In real time, gesture recognition software translates those hand movements into sounds. For example, moving your hand down the fret board makes the pitch of the sound go higher, just like on a real guitar. From the user’s point of view, it feels and sounds like you’re really playing.
Of course, you can’t do everything on the air guitar that you can do on a real guitar. For example, an actual guitar player couldn’t play “Stairway to Heaven” on it. That may sound limiting, but think about it: if the air guitar worked just like a real guitar, you’d have to spend just as much time learning how to play it! The whole point of the air guitar is that anyone can feel like a guitarist in just a few seconds. So Kanerva’s team has limited the scope of what it can do.
There are two basic modes to the air guitar: chord mode and solo mode. If you’re playing in chord mode, you can only play four different chords. Not much, but enough to play the opening chords to “Smoke on the Water” and a zillion other hard-rock classics. In solo mode, you run up and down a pentatonic E minor scale, which is a standard key in which rock guitar soloist’s play. Because there’s only so much the guitar can do, it’s pretty much impossible to play it badly. No matter how you mix and match the chords and solo notes, it’ll sound like you’re playing something.
The whole system can run on an ordinary desktop computer. A Windows version is in the works, and before long, home air guitars may become as common as X-Boxes and Gamecubes. Who knows—it might even inspire people to learn how to play the real thing.
Now try and answer these questions:
- Describe how the air guitar works.
- Why does the air guitar use only a limited number of chords and solo notes? What would happen if you made it capable of playing anything?
- What would happen if you tried to use the air guitar while wearing an orange sweater?
- What other imaginary instruments would work well with this sort of interface? Are there instruments that wouldn’t work so well? Why?
The official website of the Virtual Air Guitar Project has more information on the system and how it works.
The Virtual Reality Lab of the Swiss Federal Institute of Technology has a detailed, English-language site describing a wide variety of virtual reality projects.