


                                  - 1 -



       COMMAND

       ssssmmmmooooooootttthhhh ---- ssssmmmmooooooootttthhhh iiiimmmmaaaaggggeeee ssssuuuurrrrffffaaaacccceeee rrrroooouuuugggghhhhnnnneeeessssssss

       USAGE

       ssssmmmmooooooootttthhhh [----ttttgggg8888]

       ssssmmmmooooooootttthhhh ----pppp [_s_i_z_e__l_g [_s_i_z_e__l_t]]

       DESCRIPTION

       SSSSmmmmooooooootttthhhh enables you to modify an image or portions thereof in
       such a way that surface details tend to blend into their
       neighboring features and to be considerably less pronounced.
       The command offers a variety of choices regarding the
       orientation and degree of severity with which the smoothing
       effect can be applied.

       ----tttt        Smooth along latitudes with replacement of each
                 value by the average of itself and its neighbors
                 left and right.

       ----gggg        Smooth along longitides with replacement of each
                 value by the average of itself and its neighbors
                 above and below.

       ----8888        Smooth along longitudes and latitudes with
                 replacement of each radius by the rolling average
                 of its eight neighbors above, below, left and
                 right.  The target value itself is somewhat
                 excluded from the average.

       ----pppp        Smooth along longitudes and latitudes patchwise
                 with replacement of each radius by the rolling
                 average of the neighbors within a patch of
                 dimension size_lg * 2 + 1 by size_lt * 2 + 1
                 centered about the target point.  Includes the
                 value of the target point in the average.  The
                 special cases around the limits of the window are
                 handled with an appropriatly clipped patch.

       _s_i_z_e__l_g   Include _s_i_z_e__l_g longitudes ahead and behind in
                 each patch of the the rolling average.  For use
                 with ----pppp only. Defaults to 2.

       _s_i_z_e__l_t   Include _s_i_z_e__l_t latitudes above and below in each
                 patch of the the rolling average.  For use with ----pppp
                 only. Defaults to 6.













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       The ----pppp option allows patchwise smoothing with replacement of
       radial values with patchwise rolling average values.  The
       specification of patch size, dimensions and orientation is
       totally at your control by your choice of value for the
       _s_i_z_e__l_g and _s_i_z_e__l_t arguments.

       Perhaps a few examples of patchwise smoothing will help you
       to recognize the special case nature of the ----gggg, ----tttt and ----8888
       options relative to the more general and robust ----pppp option.

       The ssssmmmmooooooootttthhhh ----pppp 0000 1111 command results in replacement of radii by
       their rolling average with their immediate neighbors above
       and below.  The ssssmmmmooooooootttthhhh ----pppp 1111 0000 command results in replacement
       of radii by their rolling average with their immediate
       neighbors ahead and behind.  The ssssmmmmooooooootttthhhh ----pppp 1111 1111 command
       results in replacement of radii by their rolling average
       with their [(2 x _1 + 1) x (2 x _1 + 1) - 1] or 8 immediate
       neighbors above, below, ahead and behind.

       Aside from some subtle differences, these three commands are
       equivalent to ssssmmmmooooooootttthhhh ----gggg, ssssmmmmooooooootttthhhh ----tttt and ssssmmmmooooooootttthhhh ----8888
       respectively.  The ----gggg and ----tttt options do not test for voids
       and are consequently useful only on filled images.  The ----8888
       option does test for voids as does the ----pppp options and is
       virtually identical to ssssmmmmooooooootttthhhh ----pppp 1111 1111.

       CAVEATS

       Patchwise smoothing beyond the level of equivalence with the
       ----gggg and ----tttt options can literally _m_e_l_t an image.  If a lighter
       touch is desired stick with very small, i.e., (0 by 1 or 2)
       and (1 or 2 by 0), patches.

       You should note that ssssmmmmooooooootttthhhh ----pppp 0000 1111 followed by ssssmmmmooooooootttthhhh ----pppp 1111 0000
       has a much more gentle effect than ssssmmmmooooooootttthhhh ----pppp 1111 1111 by itself.

       The algorithms perform the smoothing in-place.  This causes
       the results of the smoothing of point _n,_m to affect the
       average for point _n+_1,_m+_1 and so forth.  Hence our use of
       the phrase _r_o_l_l_i_n_g _a_v_e_r_a_g_e in this description.  A better
       method might be to use a separate destination image.


















