How to plot the frequency spectrum with scipy

numpy.fft.irfft2(a, s=None, axes=(-2, -1))[source] Compute the 2-dimensional inverse FFT of a real array. Parameters: a : array_like. The input array. s : sequence of ints, optional. Shape of the inverse FFT. axes : sequence of ints, optional. The axes over which to compute the inverse fft. Default is the last two axes. Returns: out : ndarray ................
................