-------------------------------------------
entry variable: $kcnt -- integer cell size of 3D kernel
-------------------------------------------
default: 5 (unit are 1 pixel cells)

The unlabeled entry to the left of the "fwhm:"
field sets the integer cell size of the 3D
Gaussian smoothing kernel.  The units are
structural underlay pixels.  These are usually 1
mm wide with standard 'conforming' 256x256
structural scans (but 0.5 mm wide in the case of
512x512 data sets).

For the default FWHM of 1.5 pixels, the kernel
cell size is 5 (5x5x5).  If the FWHM is increasd,
the cell size should be increased, too (to about
3x the FWHM).

Computation time scales linearly with this
variable.

N.B.: this variable is also used by the local
plane of least variance (anisotropic) filter
functions (PF, PFGAU) in which case, the only
allowed values are 5 and 7.
