Stockwell transform optimization applied on the detection of split in heart sounds

The aim of this paper is to improve the energy concentration of the Stockwell transform (S-transform) in the time-frequency domain. Several methods proposed in the literature tried to introduce novel parameters to control the width of the Gaussian window in the S-transform. In this study, a modified S-transform is proposed with four parameters to control the Gaussian window width. A genetic algorithm is applied to select the optimal parameters which maximize the energy concentration measure. An application presented in this paper consists to detect split in heart sounds and calculate its duration which is valuable medical information. Comparison with other famous time-frequency transforms such as Short-time Fourier transforms (STFT) and smoothed-pseudo Wigner-Ville distribution (SPWVD) is performed and discussed.