Microsoft Research’s SoundWave, Doppler Effect for computer gesture control

Soundwave is a model input based on the detection of the movement of the hands through the sound and ultrasound. At no cost, because it uses components already installed in the PC and requires no dedicated hardware. Many possible applications and the system, although experimental, is already very precise

The DOPPLER EFFECT is well exemplified by the sound you can hear when passing a car very fast. The movement of the vehicle to perceive a change of the sound wave emitted by the engine, which in reality is always the same. And the Doppler effect is the basis of Soundwave, a Microsoft project that starts from the sound to reach the gestures with which to control an electronic device. Without the use then of a motion sensor and position such as that of Kinect, the device for Xbox which allows to interact with the game by moving the body. After that Disney thinks of a world of touch 1, Microsoft works for subtraction and replaces the gestural touch.

In Redmond have thought of using the Doppler effect as the source of information, then to understand how the computer interprets the user's hands move in front of the PC. Soundwave works by measuring what they perceive from the computer's microphone and what comes out of the speaker, after a calibration of audio and hands with the issuance of an ultrasound between 20 and 22 kHz. An effect similar to what it would be playing a theremin, a musical instrument based on electrical fields. In fact, a kind of "tuning" of the hands, which allows the system to accurately detect their behavior, through the comparison of data coming from the input and output.

Soundwave becomes able to understand how the user is moving his hands in front of the screen. There are many parameters detectable and therefore particularly complex interfaces that they could get. Measuring and mixing data on the speed, direction and spatial coverage of the motion of the hands, Soundwave returns behavior of the screen, which in the first test was easy to understand and fairly accurate, with an accuracy of 90%. Possible applications are numerous features to the already limited time, the control without external devices of a computer complex interactivity.

The real point for Soundwave to Kinect is that nature does not need to run more than simple microphones and speakers. All components at low cost, and in any case available in the computer also not more recent. Kinect is instead based on technologies that make it a dedicated input device sophisticated but costing considerably higher. And do not affect the functionality of the speakers, which must naturally remain active so Soundwave can work. At least until Microsoft developed a technology of cancellation of ambient sound.