Fast approximations to positive time-frequency distributions, with applications

We present a general approach to approximating positive time-frequency distributions (TFDs) through nonlinear combinations of spectrograms. Closed-form solutions for the combinations are obtained via optimization of entropy functionals subject to an energy constraint. We apply two such combinations to generating approximate TFDs for whale sounds and speech. Through these applications, it can be seen that these methods give results superior to that achieved with individual spectrograms, and remarkably close to the positive TFDs obtained via computationally-intensive methods