def find_first_peak(corr):
    """
    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

    """    
    ind = corr.argmax()
    s = corr.shape[1] 
    
    i = ind // s 
    j = ind %  s
    
    return i, j, corr.max()