pymovements.gaze.transforms_pl.pos2vel#

pymovements.gaze.transforms_pl.pos2vel(*, sampling_rate: float, method: str, degree: int | None = None, window_length: int | None = None, padding: str | float | int | None = 'nearest') → pl.Expr[source]#

Compute velocitiy data from positional data.

There are three methods available for velocity calculation: * savitzky_golay: velocity is calculated by a polynomial of fixed degree and window length. See savitzky_golay() for further details. * smooth: velocity is calculated from the difference of the mean values of the subsequent two samples and the preceding two samples * neighbors: velocity is calculated from difference of the subsequent sample and the preceding sample * preceding: velocity is calculated from the difference of the current sample to the preceding sample

Parameters:

  • sampling_rate – Sampling rate of input time series.

  • method – The method to use for velocity calculation.

  • degree – The degree of the polynomial to use. This has only an effect if using savitzky_golay as calculation method.

  • window_length – The window size to use. This has only an effect if using savitzky_golay as calculation method.

  • padding – The padding to use. This has only an effect if using savitzky_golay as calculation method.