Problem 2. (Filtering in the spatial domain, 10 points)
Consider a 2-D linear, shift-invariant system with impulse response
$$h = \begin{pmatrix} 0 & -1 & 0 \\ -1 & 4 & -1 \\ 0 & -1 & 0 \end{pmatrix},$$
where $\boxed{}$ represents the location of the origin. Determine the output when the input to
the system is $f[m, n] = 0.25 \cos(0.2\pi m + 0.3\pi n) + 0.5 \cos(0.7\pi m - 0.2\pi n)$, $m, n \in Z$.