Compute a Fourier transform based distance
    between two matrices.

    Inspired from Galiez et al., 2015
    (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4535829/)

def asd(M1, M2):
    """Compute a Fourier transform based distance
    between two matrices.

    Inspired from Galiez et al., 2015
    (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4535829/)
    """

    from scipy.fftpack import fft2
    spectra1 = np.abs(fft2(M1))
    spectra2 = np.abs(fft2(M2))

    return np.linalg.norm(spectra2 - spectra1)