``Symmetric_Nearest_Neighbor'' -- symmetric nearest-neighbor mean filter

purpose:

Run the symmetric nearest-neighbor (SNN) mean filter on an input volume [6]. The SNN mean filter is a nonlinear, noise-smoothing, edge-preserving filter. It also can preserve thin lines (depending on the operator window size) in images (although the sigma filter may be better for this purpose).

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 parameters ``x filter dim = '', etc., specify the size of the local operator used by the filter.

comments:

 

1. This filter may ``sharpen'' regions more impressively than the sigma filter, but the sigma filter will preserve thin lines better. The maximum-homogeneity filter sharpens noise and reduces noise better than both the SNN and sigma filters.
2. This is a moderate computation algorithm (depending on the window size).