Application of loudness/pitch/timbre decomposition operators to auditory scene analysis

Abe and Ando (see Proc. IEEE ICASSP95, p.1368-71, 1995) proposed nonlinear operators which decompose a changing energy of sound in the wavelet domain into three orthogonal components: i.e., loudness and pitch as coherent changes, and timbre as an incoherent change. They showed that they could detect the discontinuity of a single sound stream with excellent temporal resolution and sensitivity. In this paper, they extend the coherency principle so that it can describe and pursue the individual coherency of non-overlapping sound streams in the wavelet domain. It is realized by Parzen's non-parametric estimates and Kalman filtering of the loudness change rate and the pitch shift rate. Using this method, they show some experiments for the extraction of the most salient stream from multiple sound streams.