Cross-correlation filtering
Let’s write this down as an equation.
Assume the
averaging window is (2k+1)x(2k+1):
We can generalize this idea by allowing different
weights for different neighboring pixels:
This is called a
cross-correlation
operation and
written:
H is called the “filter,”
“kernel,”
or “mask.”
The above allows negative filter indices.
When
you implement need to use:
H[u+k,v+k]
instead of H[u,v]