Fig. 2
From: Frequency-dependent force direction elucidates neural control of balance
Relation between \(\theta _F\) and CoP for one simulation trial. The data were processed by filtering the CoP and \(\theta _F\) signals using a 2nd-order bandpass filter with a 0.2 Hz wide frequency band. The principal eigenvector of the covariance matrix of the filtered data was extracted. The intersection point (IP) was computed as the inverse of the angle of the principal eigenvector. Note that the time series of the data was approximated as an ellipse in this schematic illustration