Using the distance transform with masks
$$
h_f(m, n)=\left[\begin{array}{rrrrr}
\infty & 11 & \infty & 11 & \infty \\
11 & 7 & 5 & 7 & 11 \\
\infty & 5 & 0 & \infty & \infty \\
\infty & \infty & \infty & \infty & \infty \\
\infty & \infty & \infty & \infty & \infty
\end{array}\right] \text { and } h_b(m, n)=\left[\begin{array}{rrrrr}
\infty & \infty & \infty & \infty & \infty \\
\infty & \infty & \infty & \infty & \infty \\
\infty & \infty & 0 & 5 & \infty \\
11 & 7 & 5 & 7 & 11 \\
\infty & 11 & \infty & 11 & \infty
\end{array}\right]
$$
find the distance of the pixels of the $8 \times 8$ image.
$$
\left[\begin{array}{llllllll}
0 & 0 & 0 & 1 & 1 & 1 & 1 & 1 \\
0 & 0 & 0 & 0 & 1 & 1 & 1 & 1 \\
0 & 0 & 0 & 0 & 0 & 1 & 1 & 1 \\
0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 \\
0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 \\
0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 \\
0 & 0 & 0 & 0 & 0 & 0 & 0 & 1 \\
0 & 0 & 0 & 0 & 0 & 0 & 0 & 1
\end{array}\right]
$$