Demo: Phase-based Acoustic Localization and Motion Tracking for Mobile Interaction

Motion tracking, as a mechanism of mobile interaction, allows devices to get fine-gained user input by locating the real-time position of target devices (e.g., smart phones, smart watches) in the air. With the proliferation of mobile devices and smart multimedia devices (e.g., smart TV, home audio system), the ubiquitous speakers and microphones in the devices provide more diverse ways of acoustic-based mobile interaction. In this demonstration, we propose a fine-gained motion tracking system, which can be developed on commercial mobile devices and track the devices with millimeter level (mm-level) accuracy. We first compensate the phase offset between receiver and audio source at each frequency. We then use the acoustic phase change at receiver to achieve accurate distance measurement. Finally, we implement our system on off-the-shelf devices, and achieve a fine-gained motion tracking in two-dimensional space. Our experiments show that our system achieves high accuracy as well as high sensitivity: our system could detect the sight and slow movement caused by human breathing for example.