  Audio processing methods operating on a time-frequency representation of the
signal can introduce unpleasant sounding artifacts known as musical noise.
These artifacts are observed in the context of audio coding, speech
enhancement, and source separation. The change in kurtosis of the power
spectrum introduced during the processing was shown to correlate with the human
perception of musical noise in the context of speech enhancement, leading to
the proposal of measures based on it. These baseline measures are here shown to
correlate with human perception only in a limited manner. As ground truth for
the human perception, the results from two listening tests are considered: one
involving audio coding and one involving source separation. Simple but
effective perceptually motivated improvements are proposed and the resulting
new measure is shown to clearly outperform the baselines in terms of
correlation with the results of both listening tests. Moreover, with respect to
the listening test on musical noise in audio coding, the exhibited correlation
is nearly as good as the one exhibited by the Artifact-related Perceptual Score
(APS), which was found to be the best objective measure for this task. The APS
is however computationally very expensive. The proposed measure is easily
computed, requiring only a fraction of the computational cost of the APS.
