openpiv.pyprocess.piv

static pyprocess.piv(frame_a, frame_b, window_size=32, overlap=16, dt=1.0, corr_method='fft', sig2noise_method='peak2peak', sig2noise_lim=1.0)

Basic python implementation of the PIV cross-correlation algorithm.

Parameters :

frame_a : 2d np.ndarray

an two dimensions array of integers containing grey levels of the first frame.

frame_b : 2d np.ndarray

an two dimensions array of integers containing grey levels of the second frame.

window_size : int

the size of the (square) interrogation window [default: 32 pix]

overlap : int

the number of pixels by which two adjacent windows overlap [default: 16 pix]

dt : float

the time delay separating the two frames [default: 1.0]

corr_method : string

one of the two methods implemented: ‘fft’ or ‘direct’

sig2noise_method : string

defines the method of signal-to-noise-ratio measure, ‘peak2peak’ (default) or ‘peak2mean’

sig2noise_lim: float :

the limit of the signal to noise ratio, 1.0 [default] to ignore this limit

nfftx : int

the size of the 2D FFT in x-direction, [default: 2 x windows_a.shape[0] is recommended]

nffty : int

the size of the 2D FFT in y-direction, [default: 2 x windows_a.shape[1] is recommended]

Returns :

u : 2d np.ndarray

a two dimensional array containing the u velocity component, in pixels/seconds.

v : 2d np.ndarray

a two dimensional array containing the v velocity component, in pixels/seconds.

Previous topic

openpiv.pyprocess.find_subpixel_peak_position

Next topic

openpiv.process.extended_search_area_piv

This Page