•Note
that for a 256 gray level image, we can precompute all values of the
convolution and avoiding multiplication.
•
•For
the box filter, we can implement any size using 4n additions per pixel.
•
•Also
note that, by the central limit theorem, repeated box filter averaging yields
approximations to a Gaussian filter.
•
•Finally,
note that a sequence of filtering operations can be collapsed into
one by associativity.
–in
general, this is not a win, but we’ll see examples where it is ...