openpiv_cxx.process.correlation_to_displacement

openpiv_cxx.process.correlation_to_displacement(corr, n_rows=None, n_cols=None, kernel='2x3', limit_peak_search=True, thread_count=1, return_type='first_peak')

Standard subpixel estimation.

Parameters:

  • corr (3D ndarray) – A three dimensional array with axis 0 being the two dimensional correlation matrix of an interrogation window.

  • n_rows (int, optional) – Number of rows and columns of the vector field being evaluated, output of get_field_shape.

  • n_cols (int, optional) – Number of rows and columns of the vector field being evaluated, output of get_field_shape.

  • kernel (str) – Type of kernel used to find the subpixel peak. Kernels with ‘2xN’ are 2 1D subpixel estimations that are ‘N’ elements wide.

  • limit_peak_search (bool) – Limit peak search area to a quarter of the size of the interrogation window if the width and height of the interrogation window is greater than 12.

  • thread_count (int) – The number of threads to use with values < 1 automatically setting thread_count to the maximum of concurrent threads - 1.

  • return_type (str) – Which peak data to return.

Returns:

  • u, v (ndarray) – 2D array of displacements in pixels/dt.

  • peakHeight (ndarray) – 2D array of correlation peak heights

  • peak2peak (ndarray) – 2D array of signal-to-noise ratios.

  • u2, v2 (ndarray, optional) – 2D array of displacements in pixels/dt for a second peak.

  • u3, v3 (ndarray, optional) – 2D array of displacements in pixels/dt for a third peak.