The Matched Reassignment Applied to Echolocation Data

Previous studies have shown that measurements of beluga whale (Delphinapterus leucas) and bottlenose dolphin (Tur-siops truncatus) echolocation signals at off-axis angles may be well modeled using a Gaussian bell function or a chirped Gaussian function as envelope. In this paper, we apply a novel technique, the matched window reassignment, for investigation of a range of models of dolphin echolocation transients. Using a set of parameterized skewed envelopes and a dictionary-based estimation algorithm, it is shown that the Rényi entropy can be used as an evaluation measure of the model fit. Acoustic recordings from an array of hydrophones of a beluga's echolocation signal are investigated, where the Gaussian envelope frequency modulation function resulted in the lowest Rényi entropy mean and the two-parametric Gum-bel model showed the best observed fit.