def self_neighbors(matches):
    """
    Returns a pandas data series intended to be used as a mask. Each row
    is True if it is not matched to a point in the same image (good) and
    False if it is (bad.)

    Parameters
    ----------
    matches : dataframe
              the matches dataframe stored along the edge of the graph
              containing matched points with columns containing:
              matched image name, query index, train index, and
              descriptor distance
    Returns
    -------
    : dataseries
      Intended to mask the matches dataframe. True means the row is not matched to a point in the same image
      and false the row is.
    """
    return matches.source_image != matches.destination_image