Table 6. Values of SDNN, lnSDNN, RMSSD, and pNN50 (expressed as a mean ± standard deviation) derived from rPPG recordings of different lengths and from the 60 s reference (PPG) recordings together with the corresponding mean absolute errors (MAEs).
10s-1, 10s-2, and 10s-3 denote the first, second and third groups of 10 s recordings, 30s-1 and 30s-2 the first and second groups of 30 s recordings, 60s the group of 60 s recordings, avg10s the average of all 10 s recordings, and avg30s the average of all 30 s recordings.
| SDNN (ms) | MAESDNN (ms) | lnSDNN | MAElnSDNN | RMSSD (ms) | MAERMSSD (ms) | pNN50 (%) | MAEpNN50 (%) | |
|---|---|---|---|---|---|---|---|---|
| PPG (reference) | ||||||||
| 60s | 48.61 ± 16.99 | – | 3.82 ± 0.38 | – | 46.27 ± 23.78 | – | 24.14 ± 19.11 | – |
| rPPG | ||||||||
| 10s-1 | 44.79 ± 24.91 | 16.73 | 3.68 ± 0.50 | 0.36 | 45.02 ± 35.77 | 23.00 | – | – |
| 10s-2 | 38.71 ± 20.89 | 16.79 | 3.53 ± 0.51 | 0.41 | 41.31 ± 25.96 | 16.29 | – | – |
| 10s-3 | 37.85 ± 24.83 | 17.24 | 3.49 ± 0.53 | 0.43 | 39.92 ± 20.23 | 14.47 | – | – |
| avg10s | 40.45 ± 17.67 | 11.96 | 3.62 ± 0.4 | 0.27 | 42.08 ± 22.44 | 14.77 | – | – |
| 30s-1 | 48.02 ± 20.38 | 11.12 | 3.78 ± 0.43 | 0.23 | 46.02 ± 28.15 | 18.31 | 20.89 ± 16.32 | 11.16 |
| 30s-2 | 41.49 ± 19.40 | 12.36 | 3.63 ± 0.44 | 0.28 | 42.84 ± 23.41 | 14.95 | 20.46 ± 18.22 | 10.76 |
| avg30s | 44.76 ± 17.85 | 9.55 | 3.72 ± 0.40 | 0.20 | 44.43 ± 24.08 | 16.10 | 20.68 ± 16.39 | 9.99 |