def filter_ring(points, center, rminmax):
    """Filter points to be in a certain radial distance range from center.

    Parameters
    ----------
        points : np.ndarray
            Candidate points.
        center : np.ndarray or tuple
            Center position.
        rminmax : tuple
            Tuple of min and max radial distance.

    Returns
    -------
        : np.ndarray
            List of filtered points, two column array.

    """