Ambient noise tracking using signal stationarity

Abstract

A system configured to improve noise estimation while performing noise dependent volume control to reduce a sensitivity to voice activity and other non-stationary sounds. For example, a device may adaptively increase a volume level of playback audio based on an amount of ambient noise present in a noisy environment, with an amount of noise compensation determined based on an estimated noise level. To avoid overestimating the noise level during periods of voice activity (e.g., speech), loud transient sounds (e.g., slamming doors, coughing), and/or residual acoustic echo, the device may adaptively slow a noise tracking speed for non-stationary signals. For example, the device may extract features that distinguish between stationary signals and non-stationary signals and calculate a stationarity coefficient to adaptively control noise estimation. Thus, the device may use a normal noise tracking speed for stationary signals and a slower noise tracking speed for non-stationary signals.