ROCK guitarists used to rely on some nimble footwork to add all those
spine-tingling wails to their guitar solos. Soon, all they will have to do is to
open their mouths.
Musicians have long used 鈥渨ah-wah pedals鈥� to change the sound of notes on
electric guitars. The Mouthesizer, which has been developed by Michael Lyons at
the ATR Media Integration & Communication Research Labs in Kyoto, Japan, not
only replaces the pedal but also produces a wealth of other effects.
A pickup on the guitar converts the notes being played into MIDI, the
language of electronic music that can define properties of musical notes such as
their pitch and duration. Meanwhile, a miniature head-mounted digital camera
monitors the shape of your mouth and sends instructions to a synthesiser, which
modifies the MIDI properties of the notes. Stretching your mouth wide in a
soul-searching grimace produces a gritty, distorted sound, while opening and
closing the mouth yields a plaintive wah-wah effect.
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Lyons and his colleagues Michael Haehnel and Nobuji Tetsutani use a simple
facial-recognition algorithm that isolates the shadowy area inside the mouth.
This shape can be picked up by the video camera in almost any lighting
condition.
The researchers tested the invention on seven musicians, who say that the
Mouthesizer is easy to learn and is more versatile than a foot pedal. Lyons says
the mouth makes an excellent synthesiser input device because our control of
facial muscles is very precise.
Lyons is due to present his work at the annual computer graphics conference,
Siggraph 2001, in Los Angeles this week. He says: 鈥淲e have all this sensory
control over the mouth and I think it should be used.鈥� Lyons says that musicians
who play other MIDI-equipped instruments, such as keyboards, will also be able
to use the device to bend notes without using foot pedals.