pymovements.transforms.pos2vel

pymovements.transforms.pos2vel(arr: list[float] | list[list[float]] | np.ndarray, sampling_rate: float = 1000, method: str = 'smooth', **kwargs) → np.ndarray

Compute velocity time series from 2-dimensional position time series.

Methods ‘smooth’, ‘neighbors’ and ‘preceding’ are adapted from

Engbert et al.: Microsaccade Toolbox 0.9.

Parameters

• arr (array_like) – Continuous 2D position time series

• sampling_rate (int) – Sampling rate of input time series

• method (str) – Following methods are available: * 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

• kwargs (dict) – Additional keyword arguments used for savitzky golay method.

Returns

Velocity time series in input_unit / sec

Return type

np.ndarray

Raises

ValueError – If selected method is invalid, input array is too short for the selected method or the sampling rate is below zero