For a k´k filter, the
equation becomes (assume k is odd):
If we choose the origin of h, F, and
G to be the center, we can simplify:
This filtering operation is known as
a cross-correlation, written
For continuous images,
cross-correlation is defined as:
Similar to convolution:
•Convolution flips the
filter horizontally and vertically before applying it
–how does convolution
with a Gaussian filter differ from cross-correlation?