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arbitrary size kernel

  • To: mathgroup at
  • Subject: [mg101547] arbitrary size kernel
  • From: "alexxx.magni at" <alexxx.magni at>
  • Date: Fri, 10 Jul 2009 06:41:59 -0400 (EDT)

while I understand a bit the logic behind filtering in the frequency domain,
I have a problem with filtering by convolution.

I'd like to understand how to construct arbitrary-size kernels: which
are the requirements?
Specifically, I need to build the kernel of a high-pass filter able to
filter everything below some freq f_0. My problem is that all the
descriptions I found are usually for kernels in the 3x3 form, e.g.
((0.0, -1.0, 0.0),(-1.0, 5.0, -1.0),(0.0, -1.0, 0.0))

What I cannot understand is: which is the relationship between the
cutoff frequency and a given kernel shape? The kernel size? The step
between central element and side elements?

thanks for any hints or suggestions...


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