Table 1.
Mean and standard error of acceleration magnitude and duration for ground truth and three approximations (PCA, triangle, half-sine).
| Coronal direction | Sagittal direction | Axial direction | |
|---|---|---|---|
| Ground truth magnitude (rad/s2) | 818.89 ± 937.12 | 1498.10 ± 1753.40 | 655.16 ± 535.03 |
| PCA magnitude (rad/s2) | 801.41 ± 922.08 | 1460.50 ± 1736.10 | 641.52 ± 523.06 |
| Triangle magnitude (rad/s2) | 871.53 ± 1011.8 | 1625.40 ± 1923.20 | 697.04 ± 553.95 |
| Half-sine magnitude (rad/s2) | 681.25 ± 790.38 | 1269.30 ± 1500.40 | 545.64 ± 433.40 |
| Duration (ms) | 15.20 ± 6.75 | 15.00 ± 8.03 | 17.90 ± 8.45 |
The PCA magnitudes were obtained by decomposing the ground truth angular accelerations for the criterion η = 0.90, which constituted of 21 modes for coronal and sagittal directions and 20 modes for axial direction (see Supplementary Figure 3).