Evaluation of Different Wavelet Functions Applied in the Development of Digital Filters to Attenuate the Background Activity in EEG Signals

Wavelet Filter to Attenuate the Background Activity and High Frequencies in EEG Signals Applied in the Automatic Identification of Epileptiform Events

“…Four Wavelet functions were select from 65 evaluated. According to the experiments the Wavelet function Db4 proved to be the best function for the development of a digital filter in this application, according to researches performed by [9][10][11][12]. The function Db4 is indicated when there is the need to preserve the epoch of the filtered signal more like the original epoch.…”

Wavelet Filter Proposal to Attenuate the Background Activity and High Frequencies in EEG Signals

“…This work presented a study about the development of a digital filter using the detail levels of the wavelet transform to attenuate the background activity and the high frequencies in the EEG signals. Many experiments were performed and the wavelet function Db4 proved to be the best choice for the development of a digital filter in this application, as shown in researches performed by [9][10][11][12]. The function Db4 is indicated when there is the need to preserve the epoch of the filtered signal more like the original epoch.…”

“…The wavelet multiresolution analysis is based in the computational implementation of the discrete wavelet transform. The algorithm decomposes a discrete signal using filter banks [6][7][8]12]. The set of filters H[n] extract the average characteristics, defined as approximations of the signal x and added to a set of filters G[n] extract the features of high frequency defined as details of the signal x[n] ( Figure 2).…”