On the use of time-frequency warping operators for analysis of marine-mammal signals

Processing marine-mammal signals for passive oceanic acoustic tomography or species classification are problems that have recently attracted attention in the scientific literature. Practically, it has been observed that the time-frequency structures of the marine-mammal signals are generally non-linear. This fact dramatically affects the performances achieved by the Cohen\´s class methods, knowing that these methods correctly perform only for linear time-frequency structures. Fortunately, it is possible to generate other classes of time-frequency representations (TFRs) using the warping operator principle. Based on this principle, we propose a new method for marine-mammal signal characterization. More precisely, many warping operators are used to "linearize" the time-frequency content of the signal. Furthermore, the chirp-like structures are estimated. The results obtained for real data illustrate the attractive outlines of the proposed method.