Table 8.
Index | Domain | Num. of features | Motivation |
---|---|---|---|
1 | Time interval | 20 | The time interval of each state has physiological meaning based on heart physiology. |
2 | Frequency spectrum of state | 308 | To reflect the frequency spectrum within state. |
3 | State amplitude | 12 | The amplitude is related to the heart hemodynamics. |
4 | Energy | 47 | To reflect energy distribution with respect to frequency band |
5 | Frequency spectrum of records | 27 | To reflect frequency spectrum within records |
6 | Cepstrum | 65 | To reflect the acoustic properties. |
7 | Cyclostationary | 4 | To reflect the degree of signal repetition. |
8 | High-order statistics | 16 | To reflect the skewness and kurtosis of each signal state. |
9 | Entropy | 16 | To reflect the PCG signal inherent complexity. |
Total | - - | 515 | - - |