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- purpose:
- This filter first applies a window average
and then a local minimum operation to an input volume. It reduces
noise and makes a volume easier to segment. Use this filter when
the regions of interest are dim (the filter favors dim
regions). Also, see the function ``ave_max''.
- input:
- An 8-bit volume.
- output:
- An 8-bit volume.
- parameters:
- Default parameters menu is
x filter dim = 3
*
y filter dim = 3
*
z filter dim = 3
*
no. of iterations = 1
*
input from vol # = 0
*
copy output to vol # = 0
*
The window average and local minimum operations use the same
operator size.
- comments:
-
- The filter is similar to a lowpass filter, yet the
minimum operation makes it nonlinear. Use it to bring out
dim regions.
- You can do a better version of this function by first
doing a hamming lowpass filter (``lowpass'' in the
``enhance'' category) and then running
a local minimum (``min'' in the ``morphology'' category).
- Moderate computation required.
Updated:
Fri May 19 14:39:07 CDT
Copyright 1994-99 Division of Physiologic Imaging, Dept. of Radiology, Univ. of Iowa
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