Exploring the Resolution Limit for In-Air Synthetic-Aperture Audio Imaging

SONAR imaging can detect reflecting objects in the dark and around corners, however many SONAR systems require large phased-arrays and immobile equipment. In order to enable sound imaging with a mobile device, one can move a microphone and speaker in the air to form a large synthetic aperture. We demonstrate resolution limited audio images using a moving microphone and speaker of a mannequin in free-space and a mannequin located around a corner. This paper also explores the 2D resolution limit due to aperture size as well as the time resolution limit due to bandwidth, and proposes Continuous Basis Pursuits (CBP) to super-resolve.