def find_first_peak(corr):
ind = corr.argmax()<EOL>s = corr.shape[<NUM_LIT:1>] <EOL>i = ind // s <EOL>j = ind %  s<EOL>return i, j, corr.max()<EOL>
Find row and column indices of the first correlation peak.

Parameters
----------
corr : np.ndarray
    the correlation map

Returns
-------
i : int
    the row index of the correlation peak

j : int
    the column index of the correlation peak    

corr_max1 : int
    the value of the correlation peak

Original code from openPIV pyprocess