AIM

Abstract

The popularity of smartphones has grown at an unprecedented rate, which makes smartphone based imaging especially appealing. In this paper, we develop a novel acoustic imaging system using only an off-the-shelf smartphone. It is an attractive alternative to camera based imaging under darkness and obstruction. Our system is based on Synthetic Aperture Radar (SAR). To image an object, a user moves a phone along a predefined trajectory to mimic a virtual sensor array. SAR based imaging poses several new challenges in our context, including strong self and background interference, deviation from the desired trajectory due to hand jitters, and severe speaker/microphone distortion. We address these challenges by developing a 2-stage interference cancellation scheme, a new algorithm to compensate trajectory errors, and an effective method to minimize the impact of signal distortion. We implement a proof-of-concept system on Samsung S7. Our results demonstrate the feasibility and effectiveness of acoustic imaging on a mobile.