Audio Activity and Anomaly Detection

Audio anomaly detection identifies events or processes that differ from normal acoustic behaviour. Mechanical faults, impacts, alarms, friction and unusual environmental sounds are common examples.

Model of normal sound

Healthy-machine or normal-environment recordings can be represented with log-Mel spectrograms, MFCCs or learned embeddings. One-class models, density estimators and autoencoders assign anomaly scores to new observations.

This is an acoustic application of the broader anomaly detection problem.

Transient and gradual changes

Glass breaking is short and impulsive, while bearing wear may appear as a gradual spectral trend over days or weeks. These cases require different window lengths, temporal context and decision logic.

Operating regime

Machine speed, load, microphone distance and background noise change the normal acoustic distribution. The model should therefore be interpreted together with operating conditions.

Additional sensors such as vibration, temperature or vision can provide complementary evidence when their timestamps are aligned reliably.