Audio denoising by time-frequency block thresholding

Removing noise from audio signals requires a non-diagonal processing of time-frequency coefficients to avoid producing "musical noise." State of the art algorithms perform a parameterized filtering of spectrogram coefficients with empirically fixed parameters. A block thresholding estimation procedure is introduced, which adjusts all parameters adaptively to signal property by minimizing a Stein estimation of the risk. Numerical experiments demonstrate the performance and robustness of this procedure through objective and subjective evaluations.