Consider a 2-D LSI system whose impulse response $h(n_1, n_2)$ has first-quadrant support. When the input $x(n_1, n_2)$ to the system is given by
$x(n_1, n_2) = 2^{n_1 n_2} u(n_1, n_2)$,
some portion of the output $y(n_1, n_2)$ has been observed. Suppose the observed portion
of $y(n_1, n_2)$ is as shown in the following figure.
$n_2$
y$(n_1, n_2)$
not observed
outside the
boundary
$n_1$
Figure P1.9
Determine $h(1, 1)$, the impulse response $h(n_1, n_2)$ evaluated at $n_1 = n_2 = 1$.