``Median'' -- a median filter

purpose:

Apply a median filter to an input volume [24]; i.e., for each voxel, assign the median value of voxels within an prespecified window size to the voxel. This nonlinear filter is good for reducing salt-and-pepper noise (speckly noise). Also, it (tries to) preserves edges, while acting much like a lowpass filter.

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

comments:

 

1. While the median filter is popular, a few of the other filters can provide better performance (the maximum-homogeneity, sigma, symmetric nearest-neighbor).
2. This function is slow. The computation time goes up as the size of the window.
3. While the median filter is popular, a few of the other filters can provide better performance (the maximum-homogeneity, sigma, symmetric nearest-neighbor).