``Lowpass'' -- lowpass filter

purpose:

Apply a lowpass filter to an input volume.

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
option = hamming
no. of iterations = 1
input from vol # = 0
copy output to vol # = 0

Two options are possible: the Hamming window [22] and a simple window average.

comments:

 

1. The Hamming window is a true lowpass filter. The simple window average, often touted as a lowpass filter, is not, since its frequency response goes as sin(x)/x (large sidelobes in the frequency domain!) [4]. Thus, I recommend using the Hamming window.
2. For a well-defined Hamming-window operator, use at least a dimension=5 operator.
3. Moderate computation time required.