Audio scene monitoring using redundant ad-hoc microphone array networks

TL;DR

This paper introduces a system for localizing sound sources in a room using multiple ad-hoc microphone arrays, employing PCA and affine transformation methods that require minimal training and no precise array placement.

Contribution

The paper proposes two novel localization methods using PCA and affine transformations that operate with minimal labeled data and no need for exact array locations.

Findings

Both methods accurately localize sound sources with few anchor points.

The PCA-based method is less robust to missing data but requires fewer training requirements.

The system demonstrates effective localization with IoT microphone arrays in an office environment.

Abstract

We present a system for localizing sound sources in a room with several ad-hoc microphone arrays. Each circular array performs direction of arrival (DOA) estimation independently using commercial software. The DOAs are fed to a fusion center, concatenated, and used to perform the localization based on two proposed methods, which require only few labeled source locations (anchor points) for training. The first proposed method is based on principal component analysis (PCA) of the observed DOA and does not require any knowledge of anchor points. The array cluster can then perform localization on a manifold defined by the PCA of concatenated DOAs over time. The second proposed method performs localization using an affine transformation between the DOA vectors and the room manifold. The PCA has fewer requirements on the training sequence, but is less robust to missing DOAs from one of the arrays. The methods are demonstrated with five IoT 8-microphone circular arrays, placed at unspecified fixed locations in an office. Both the PCA and the affine method can easily map out a rectangle based on a few anchor points with similar accuracy. The proposed methods provide a step towards monitoring activities in a smart home and require little installation effort as the array locations are not needed.