DESCRIPTION:

Do a separated maximum filter on axis. Size determines the
half width ofthe window, fromset contains the classes
which are considered for maximum determination, toset the
classes which may be written to.
Please note, that unexpected results may happen, if a class
is in toset, but not in fromset. In this case, values may
_rise_ because the minimum is calculated just from fromset
voxels, which may be higher than the toset value.