Table 1 Definition of extracted features from PPG and APG.
Type (count) | Feature name | Definition |
|---|---|---|
Time-domain (14) | Tp, Td, HR | TP-TN, TD-TN, 60,000/(TN+1-TN) |
RI, SI, T_RD | YD/YP, Height/(TD-TP), (TP-TN)/(TN+1-TP) | |
Rslop, Dslop | (YP-YN)/(TP-TN), (YP-YN)/(TN+1-TP) | |
Rarea | \(\int_{{T_{N} }}^{{T_{P} }} {Y_{PPG} dt} /\int_{{T_{P} }}^{{T_{N + 1} }} {Y_{PPG} dt}\) | |
VDab, VDae | YA/YB, YA/YE | |
W25, W50, W75 | Pulse width at the 25%, 50% and 75% height of the systolic peak, respectively | |
Frequency-domain (5) | H1–H5 | Normalized harmonic power in the frequency domain, using Welch's method (O2/O1–O6/O1) |
Wavelet packet decomposition energy features (11) | E1–E10, Eall | E1–E10: Normalized energy obtained by wavelet packet decomposition, from 0 to 9.77 Hz (0.977 Hz for each); Eall: The total energy of PPG signal (0–250 Hz) |
