Supervised time-frequency reassignment

The reassignment method has been proved to improve the time-frequency representation of deterministic signals and especially of "chirp-like" FM signals. Unfortunately, reassignment presents some limitations when broadband noise is present. In this case, the squeezing process yields peaked areas in noise-only regions: this drawback should be avoided, since a rather flat energy distribution should be expected there. We propose in this paper an improvement to the spectrogram reassignment, based on a multi-window procedure, which brings a solution to this kind of problem. The efficiency of the proposed method is illustrated by numerical simulations and supported by quantitative measures.