openpiv.validation.global_std

openpiv.validation.global_std(u: numpy.ndarray, v: numpy.ndarray, std_threshold: int = 5) → numpy.ndarray

Eliminate spurious vectors with a global threshold defined by the standard deviation

This validation method tests for the spatial consistency of the data and outliers vector are replaced with NaN (Not a Number) if at least one of the two velocity components is out of a specified global range.

Parameters:

• u (2d masked np.ndarray) – a two dimensional array containing the u velocity component.
• v (2d masked np.ndarray) – a two dimensional array containing the v velocity component.
• std_threshold (float) – If the length of the vector (actually the sum of squared components) is larger than std_threshold times standard deviation of the flow field, then the vector is treated as an outlier. [default = 3]

Returns:

flag – a boolean array. True elements corresponds to outliers.

Return type:

boolean 2d np.ndarray