openpiv.pyprocess.find_subpixel_peak_position

openpiv.pyprocess.find_subpixel_peak_position(corr, subpixel_method='gaussian')

Find subpixel approximation of the correlation peak.

This function returns a subpixels approximation of the correlation peak by using one of the several methods available. If requested, the function also returns the signal to noise ratio level evaluated from the correlation map.

Parameters

• corr (np.ndarray) – the correlation map.

• subpixel_method (string) – one of the following methods to estimate subpixel location of the peak: ‘centroid’ [replaces default if correlation map is negative], ‘gaussian’ [default if correlation map is positive], ‘parabolic’.

Returns

subp_peak_position – the fractional row and column indices for the sub-pixel approximation of the correlation peak. If the first peak is on the border of the correlation map or any other problem, the returned result is a tuple of NaNs.

Return type

two elements tuple