“…By contrast, the feature extraction stage has seen a more restricted selection, with the main methods using either a time-frequency (TF) approach [8], or the use of a discrete wavelet transform (DWT) [9]. More recently, the current methods of feature extraction have been classified into so-called T1, T2, and T3 spaces (using global, mean, and single valued parameters respectively), and an evaluation of their performance carried out [5]. The results of this analysis were that the T2 (such as the DWT) and T3 spaces showed similar performance, although T3 was marginally better.…”