AudioIO: Indoor Outdoor Detection on Smartphones via Active Sound Probing

The contextual status of mobile devices is fundamental information for many smart city applications. In this paper we present AudioIO, an active sound probing based method to tackle the problem of Indoor Outdoor (IO) detection for smartphones. We utilize the embedded speaker and microphone to emit probing signal and collect reverberation of surrounding environments. A SVM classifier is trained on the features extracted from the reverberation. We test its performance in various scenarios with different probing signals (MLS and chirp), noise levels, and device types. AudioIO achieves above 90% accuracy for both MLS and chirp signals with any tested noise levels and device types.