Autocorrelation function of a random field
= Autocorrelation function of a random field
{title2=$C(\mathbf s)$}
For a zero-mean <stationary Gaussian random field> $V(\mathbf r)$, the autocorrelation function is
$$
C_V(\mathbf s)
=\mathbb E[V(\mathbf r)V(\mathbf r+\mathbf s)],
$$
which is independent of $\mathbf r$. Its <Fourier transform> is the spatial power spectral density.