SYNOPSIS:
    NLGPN axis sigma sigmaw fx dead

DESCRIPTION:
    Do a separated nonlinear gaussian filtering.
    This filter has enhancing properties for edges that are at least
    about "dead" high.

SEE ALSO:
    FILTB_NLC, FILTB_NLC2, FILTB_NLD, NLGS, NLGPN2,
    backingstore, COPY_BACKTOGREY, XCHG_GREYANDBACK, ERASE_BACK
