%!PS-Adobe-2.0 %%Version: 0.1 %%DocumentFonts: (atend) %%Pages: (atend) %%EndComments % % Version 3.3.2 prologue for troff files. % /#copies 1 store /aspectratio 1 def /formsperpage 1 def /landscape false def /linewidth .3 def /magnification 1 def /margin 0 def /orientation 0 def /resolution 720 def /rotation 1 def /xoffset 0 def /yoffset 0 def /roundpage true def /useclippath true def /pagebbox [0 0 612 792] def /R /Times-Roman def /I /Times-Italic def /B /Times-Bold def /BI /Times-BoldItalic def /H /Helvetica def /HI /Helvetica-Oblique def /HB /Helvetica-Bold def /HX /Helvetica-BoldOblique def /CW /Courier def /CO /Courier def /CI /Courier-Oblique def /CB /Courier-Bold def /CX /Courier-BoldOblique def /PA /Palatino-Roman def /PI /Palatino-Italic def /PB /Palatino-Bold def /PX /Palatino-BoldItalic def /Hr /Helvetica-Narrow def /Hi /Helvetica-Narrow-Oblique def /Hb /Helvetica-Narrow-Bold def /Hx /Helvetica-Narrow-BoldOblique def /KR /Bookman-Light def /KI /Bookman-LightItalic def /KB /Bookman-Demi def /KX /Bookman-DemiItalic def /AR /AvantGarde-Book def /AI /AvantGarde-BookOblique def /AB /AvantGarde-Demi def /AX /AvantGarde-DemiOblique def /NR /NewCenturySchlbk-Roman def /NI /NewCenturySchlbk-Italic def /NB /NewCenturySchlbk-Bold def /NX /NewCenturySchlbk-BoldItalic def /ZD /ZapfDingbats def /ZI /ZapfChancery-MediumItalic def /S /S def /S1 /S1 def /GR /Symbol def /inch {72 mul} bind def /min {2 copy gt {exch} if pop} bind def /setup { counttomark 2 idiv {def} repeat pop landscape {/orientation 90 orientation add def} if /scaling 72 resolution div def linewidth setlinewidth 1 setlinecap pagedimensions xcenter ycenter translate orientation rotation mul rotate width 2 div neg height 2 div translate xoffset inch yoffset inch neg translate margin 2 div dup neg translate magnification dup aspectratio mul scale scaling scaling scale addmetrics 0 0 moveto } def /pagedimensions { useclippath userdict /gotpagebbox known not and { /pagebbox [clippath pathbbox newpath] def roundpage currentdict /roundpagebbox known and {roundpagebbox} if } if pagebbox aload pop 4 -1 roll exch 4 1 roll 4 copy landscape {4 2 roll} if sub /width exch def sub /height exch def add 2 div /xcenter exch def add 2 div /ycenter exch def userdict /gotpagebbox true put } def /addmetrics { /Symbol /S null Sdefs cf /Times-Roman /S1 StandardEncoding dup length array copy S1defs cf } def /pagesetup { /page exch def currentdict /pagedict known currentdict page known and { page load pagedict exch get cvx exec } if } def /decodingdefs [ {counttomark 2 idiv {y moveto show} repeat} {neg /y exch def counttomark 2 idiv {y moveto show} repeat} {neg moveto {2 index stringwidth pop sub exch div 0 32 4 -1 roll widthshow} repeat} {neg moveto {spacewidth sub 0.0 32 4 -1 roll widthshow} repeat} {counttomark 2 idiv {y moveto show} repeat} {neg setfunnytext} ] def /setdecoding {/t decodingdefs 3 -1 roll get bind def} bind def /w {neg moveto show} bind def /m {neg dup /y exch def moveto} bind def /done {/lastpage where {pop lastpage} if} def /f { dup /font exch def findfont exch dup /ptsize exch def scaling div dup /size exch def scalefont setfont linewidth ptsize mul scaling 10 mul div setlinewidth /spacewidth ( ) stringwidth pop def } bind def /changefont { /fontheight exch def /fontslant exch def currentfont [ 1 0 fontheight ptsize div fontslant sin mul fontslant cos div fontheight ptsize div 0 0 ] makefont setfont } bind def /sf {f} bind def /cf { dup length 2 idiv /entries exch def /chtab exch def /newencoding exch def /newfont exch def findfont dup length 1 add dict /newdict exch def {1 index /FID ne {newdict 3 1 roll put}{pop pop} ifelse} forall newencoding type /arraytype eq {newdict /Encoding newencoding put} if newdict /Metrics entries dict put newdict /Metrics get begin chtab aload pop 1 1 entries {pop def} for newfont newdict definefont pop end } bind def % % A few arrays used to adjust reference points and character widths in some % of the printer resident fonts. If square roots are too high try changing % the lines describing /radical and /radicalex to, % % /radical [0 -75 550 0] % /radicalex [-50 -75 500 0] % % Move braceleftbt a bit - default PostScript character is off a bit. % /Sdefs [ /bracketlefttp [201 500] /bracketleftbt [201 500] /bracketrighttp [-81 380] /bracketrightbt [-83 380] /braceleftbt [203 490] /bracketrightex [220 -125 500 0] /radical [0 0 550 0] /radicalex [-50 0 500 0] /parenleftex [-20 -170 0 0] /integral [100 -50 500 0] /infinity [10 -75 730 0] ] def /S1defs [ /underscore [0 80 500 0] /endash [7 90 650 0] ] def % % Tries to round clipping path dimensions, as stored in array pagebbox, so they % match one of the known sizes in the papersizes array. Lower left coordinates % are always set to 0. % /roundpagebbox { 7 dict begin /papersizes [8.5 inch 11 inch 14 inch 17 inch] def /mappapersize { /val exch def /slop .5 inch def /diff slop def /j 0 def 0 1 papersizes length 1 sub { /i exch def papersizes i get val sub abs dup diff le {/diff exch def /j i def} {pop} ifelse } for diff slop lt {papersizes j get} {val} ifelse } def pagebbox 0 0 put pagebbox 1 0 put pagebbox dup 2 get mappapersize 2 exch put pagebbox dup 3 get mappapersize 3 exch put end } bind def %%EndProlog %%BeginSetup mark % % Encoding vector and redefinition of findfont for the ISO Latin1 standard. % The 18 characters missing from ROM based fonts on older printers are noted % below. % /ISOLatin1Encoding [ /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /space /exclam /quotedbl /numbersign /dollar /percent /ampersand /quoteright /parenleft /parenright /asterisk /plus /comma /minus /period /slash /zero /one /two /three /four /five /six /seven /eight /nine /colon /semicolon /less /equal /greater /question /at /A /B /C /D /E /F /G /H /I /J /K /L /M /N /O /P /Q /R /S /T /U /V /W /X /Y /Z /bracketleft /backslash /bracketright /asciicircum /underscore /quoteleft /a /b /c /d /e /f /g /h /i /j /k /l /m /n /o /p /q /r /s /t /u /v /w /x /y /z /braceleft /bar /braceright /asciitilde /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /dotlessi /grave /acute /circumflex /tilde /macron /breve /dotaccent /dieresis /.notdef /ring /cedilla /.notdef /hungarumlaut /ogonek /caron /space /exclamdown /cent /sterling /currency /yen /brokenbar % missing /section /dieresis /copyright /ordfeminine /guillemotleft /logicalnot /hyphen /registered /macron /degree % missing /plusminus % missing /twosuperior % missing /threesuperior % missing /acute /mu % missing /paragraph /periodcentered /cedilla /onesuperior % missing /ordmasculine /guillemotright /onequarter % missing /onehalf % missing /threequarters % missing /questiondown /Agrave /Aacute /Acircumflex /Atilde /Adieresis /Aring /AE /Ccedilla /Egrave /Eacute /Ecircumflex /Edieresis /Igrave /Iacute /Icircumflex /Idieresis /Eth % missing /Ntilde /Ograve /Oacute /Ocircumflex /Otilde /Odieresis /multiply % missing /Oslash /Ugrave /Uacute /Ucircumflex /Udieresis /Yacute % missing /Thorn % missing /germandbls /agrave /aacute /acircumflex /atilde /adieresis /aring /ae /ccedilla /egrave /eacute /ecircumflex /edieresis /igrave /iacute /icircumflex /idieresis /eth % missing /ntilde /ograve /oacute /ocircumflex /otilde /odieresis /divide % missing /oslash /ugrave /uacute /ucircumflex /udieresis /yacute % missing /thorn % missing /ydieresis ] def /NewFontDirectory FontDirectory maxlength dict def % % Apparently no guarantee findfont is defined in systemdict so the obvious % % systemdict /findfont get exec % % can generate an error. So far the only exception is a VT600 (version 48.0). % userdict /@RealFindfont known not { userdict begin /@RealFindfont systemdict begin /findfont load end def end } if /findfont { dup NewFontDirectory exch known not { dup %dup systemdict /findfont get exec % not always in systemdict dup userdict /@RealFindfont get exec dup /Encoding get StandardEncoding eq { dup length dict begin {1 index /FID ne {def}{pop pop} ifelse} forall /Encoding ISOLatin1Encoding def currentdict end /DummyFontName exch definefont } if NewFontDirectory 3 1 roll put } if NewFontDirectory exch get } bind def setup %%EndSetup %%Page: 1 1 /saveobj save def mark 1 pagesetup 12 /Times-Bold f (Pnmnlfilt) 2285 1230 w (User) 2804 1230 w (Manual) 3073 1230 w 10 /Times-Bold f (pnmnlfilt) 720 1920 w 10 /Times-Roman f (Updated: 5 February 1993) 720 2076 w (Table Of Contents) 720 2196 w 10 /Times-Bold f (NAME) 720 2436 w 10 /Times-Roman f (pnmnlfilt \255 non\255linear filters: smooth, alpha trim mean, optimal estimation 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4863 4248 w (trolled) 720 4368 w (by) 1008 4368 w (the) 1135 4368 w (radius) 1284 4368 w (parameter.) 1555 4368 w (A) 2005 4368 w (radius) 2104 4368 w (value) 2374 4368 w (of) 2616 4368 w (0.3333) 2725 4368 w (means) 3026 4368 w (that) 3307 4368 w (the) 3483 4368 w (7) 3631 4368 w (hexagons) 3707 4368 w (exactly) 4110 4368 w (fit) 4424 4368 w (into) 4539 4368 w (the) 4721 4368 w (cen\255) 4869 4368 w (ter) 720 4488 w (pixel) 853 4488 w (\(ie.) 1081 4488 w (there) 1264 4488 w (will) 1491 4488 w (be) 1675 4488 w (no) 1797 4488 w (filtering) 1925 4488 w (effect\).) 2275 4488 w (A) 2587 4488 w (radius) 2687 4488 w (value) 2959 4488 w (of) 3203 4488 w (1.0) 3314 4488 w (means) 3467 4488 w (that) 3750 4488 w (the) 3928 4488 w (7) 4078 4488 w (hexagons) 4156 4488 w (exactly) 4561 4488 w (fit) 4878 4488 w (a) 4996 4488 w (3x3 pixel array.) 720 4608 w 10 /Times-Bold f (Alpha trimmed mean filter \(0.0 ) 720 4848 w 10 /S f (<) 2079 4848 w 10 /Times-Bold f (= alpha ) 2134 4848 w 10 /S f (<) 2481 4848 w 10 /Times-Bold f (= 0.5\)) 2536 4848 w 10 /Times-Roman f (The) 720 5040 w (value) 909 5040 w (of) 1159 5040 w (the) 1276 5040 w (center) 1432 5040 w (pixel) 1709 5040 w (will) 1943 5040 w (be) 2133 5040 w (replaced) 2261 5040 w (by) 2633 5040 w (the) 2768 5040 w (mean) 2925 5040 w (of) 3176 5040 w (the) 3294 5040 w (7) 3451 5040 w (hexagon) 3536 5040 w (values,) 3909 5040 w (but) 4224 5040 w (the) 4387 5040 w (7) 4544 5040 w (values) 4629 5040 w (are) 4919 5040 w (sorted) 720 5160 w (by) 992 5160 w (size) 1120 5160 w (and) 1303 5160 w (the) 1475 5160 w (top) 1625 5160 w (and) 1781 5160 w (bottom) 1953 5160 w (alpha) 2265 5160 w (portion) 2509 5160 w (of) 2826 5160 w (the) 2937 5160 w (7) 3087 5160 w (are) 3165 5160 w (excluded) 3313 5160 w (from) 3700 5160 w (the) 3921 5160 w (mean.) 4070 5160 w (This) 4363 5160 w (implies) 4568 5160 w (that) 4890 5160 w (an) 720 5280 w (alpha) 841 5280 w (value) 1084 5280 w (of) 1327 5280 w (0.0) 1437 5280 w (gives) 1589 5280 w (the) 1827 5280 w (same) 1976 5280 w (sort) 2208 5280 w (of) 2385 5280 w (output) 2495 5280 w (as) 2778 5280 w (a) 2888 5280 w (normal) 2960 5280 w (convolution) 3271 5280 w (\(ie.) 3777 5280 w (averaging) 3935 5280 w (or) 4356 5280 w (smoothing) 4467 5280 w (fil\255) 4918 5280 w (ter\),) 720 5400 w (where) 909 5400 w (radius) 1178 5400 w (will) 1448 5400 w (determine) 1630 5400 w (the) 2055 5400 w ("strength") 2203 5400 w (of) 2633 5400 w (the) 2742 5400 w (filter.) 2890 5400 w (A) 3135 5400 w (good) 3233 5400 w (value) 3459 5400 w (to) 3701 5400 w (start from for subtle filtering is) 3805 5400 w (alpha = 0.0, radius = 0.55 For a more blatant effect, try alpha 0.0 and radius 1.0) 720 5520 w (An) 720 5676 w (alpha) 872 5676 w (value) 1118 5676 w (of) 1364 5676 w (0.5) 1477 5676 w (will) 1632 5676 w (cause) 1818 5676 w (the) 2069 5676 w (median) 2221 5676 w (value) 2545 5676 w (of) 2791 5676 w (the) 2904 5676 w (7) 3056 5676 w (hexagons) 3136 5676 w (to) 3543 5676 w (be) 3651 5676 w (used) 3775 5676 w (to) 3988 5676 w (replace) 4096 5676 w (the) 4413 5676 w (center) 4566 5676 w (pixel) 4840 5676 w (value.) 720 5796 w (This) 991 5796 w (sort) 1199 5796 w (of) 1379 5796 w (filter) 1492 5796 w (is) 1716 5796 w (good) 1813 5796 w (for) 2043 5796 w (eliminating) 2189 5796 w ("pop") 2675 5796 w (or) 2937 5796 w (single) 3050 5796 w (pixel) 3319 5796 w (noise) 3549 5796 w (from) 3790 5796 w (an) 4014 5796 w (image) 4138 5796 w (without) 4412 5796 w (spread\255) 4747 5796 w (ing the noise out or smudging features on the image. Judicious) 720 5916 w (use) 3247 5916 w (of) 3406 5916 w (the) 3515 5916 w (radius) 3663 5916 w (parameter) 3933 5916 w (will) 4357 5916 w (fine) 4539 5916 w (tune) 4720 5916 w (the) 4918 5916 w (filtering.) 720 6036 w (Intermediate) 1100 6036 w (values) 1637 6036 w (of) 1925 6036 w (alpha) 2041 6036 w (give) 2290 6036 w (effects) 2495 6036 w (somewhere) 2793 6036 w (between) 3280 6036 w (smoothing) 3645 6036 w (and) 4101 6036 w ("pop") 4278 6036 w (noise) 4543 6036 w (reduc\255) 4786 6036 w (tion.) 720 6156 w (For) 934 6156 w (subtle) 1106 6156 w (filtering) 1378 6156 w (try) 1733 6156 w (starting) 1877 6156 w (with) 2210 6156 w (values) 2421 6156 w (of) 2709 6156 w (alpha) 2825 6156 w (=) 3074 6156 w (0.4,) 3163 6156 w (radius) 3346 6156 w (=) 3624 6156 w (0.6) 3714 6156 w (For) 3873 6156 w (a) 4046 6156 w (more) 4124 6156 w (blatant) 4363 6156 w (effect) 4669 6156 w (try) 4929 6156 w (alpha = 0.5, radius = 1.0) 720 6276 w 10 /Times-Bold f (Optimal estimation smoothing. \(1.0 ) 720 6516 w 10 /S f (<) 2248 6516 w 10 /Times-Bold f (= alpha ) 2303 6516 w 10 /S f (<) 2650 6516 w 10 /Times-Bold f (= 2.0\)) 2705 6516 w 10 /Times-Roman f (This) 720 6708 w (type) 928 6708 w (of) 1130 6708 w (filter) 1243 6708 w (applies) 1468 6708 w (a) 1782 6708 w (smoothing) 1857 6708 w (filter) 2311 6708 w (adaptively) 2536 6708 w (over) 2983 6708 w (the) 3191 6708 w (image.) 3344 6708 w (For) 3669 6708 w (each) 3839 6708 w (pixel) 4052 6708 w (the) 4283 6708 w (variance) 4436 6708 w (of) 4804 6708 w (the) 4918 6708 w (surrounding) 720 6828 w (hexagon) 1236 6828 w (values) 1607 6828 w (is) 1895 6828 w (calculated,) 1995 6828 w (and) 2457 6828 w (the) 2634 6828 w (amount) 2789 6828 w (of) 3121 6828 w (smoothing) 3236 6828 w (is) 3691 6828 w (made) 3790 6828 w (inversely) 4038 6828 w (proportional) 4436 6828 w (to) 4962 6828 w (it.) 720 6948 w (The) 828 6948 w (idea) 1010 6948 w (is) 1203 6948 w (that) 1297 6948 w (if) 1474 6948 w (the) 1563 6948 w (variance) 1713 6948 w (is) 2078 6948 w (small) 2173 6948 w (then) 2418 6948 w (it) 2618 6948 w (is) 2702 6948 w (due) 2797 6948 w (to) 2969 6948 w (noise) 3075 6948 w (in) 3314 6948 w (the) 3420 6948 w (image,) 3570 6948 w (while) 3867 6948 w (if) 4117 6948 w (the) 4206 6948 w (variance) 4356 6948 w (is) 4721 6948 w (large,) 4816 6948 w (it) 720 7068 w (is) 807 7068 w (because) 905 7068 w (of) 1251 7068 w ("wanted") 1365 7068 w (image) 1765 7068 w (features.) 2039 7068 w (As) 2409 7068 w (usual) 2550 7068 w (the) 2791 7068 w (radius) 2943 7068 w (parameter) 3217 7068 w (controls) 3645 7068 w (the) 3997 7068 w (effective) 4149 7068 w (radius,) 4527 7068 w (but) 4826 7068 w (it) 4984 7068 w (probably) 720 7188 w (advisable) 1108 7188 w (to) 1519 7188 w (leave) 1631 7188 w (the) 1875 7188 w (radius) 2031 7188 w (between) 2309 7188 w (0.8) 2675 7188 w (and) 2834 7188 w (1.0) 3012 7188 w (for) 3171 7188 w (the) 3321 7188 w (variance) 3477 7188 w (calculation) 3848 7188 w (to) 4320 7188 w (be) 4432 7188 w (meaningful.) 4560 7188 w (The) 720 7308 w (alpha) 913 7308 w (parameter) 1167 7308 w (sets) 1603 7308 w (the) 1791 7308 w (noise) 1951 7308 w (threshold,) 2200 7308 w (over) 2635 7308 w (which) 2850 7308 w (less) 3131 7308 w (smoothing) 3318 7308 w (will) 3778 7308 w (be) 3971 7308 w (done.) 4102 7308 w (This) 4383 7308 w (means) 4598 7308 w (that) 4890 7308 w cleartomark showpage saveobj restore %%EndPage: 1 1 %%Page: 2 2 /saveobj save def mark 2 pagesetup 10 /Times-Roman f (\255 2 \255) 2797 480 w (small) 720 840 w (values) 971 840 w (of) 1260 840 w (alpha) 1377 840 w (will) 1627 840 w (give) 1817 840 w (the) 2023 840 w (most) 2179 840 w (subtle) 2408 840 w (filtering) 2681 840 w (effect,) 3037 840 w (while) 3322 840 w (large) 3578 840 w (values) 3811 840 w (will) 4100 840 w (tend) 4290 840 w (to) 4497 840 w (smooth) 4610 840 w (all) 4940 840 w (parts) 720 960 w (of) 943 960 w (the) 1055 960 w (image.) 1206 960 w (You) 1504 960 w (could) 1705 960 w (start) 1956 960 w (with) 2157 960 w (values) 2364 960 w (like) 2648 960 w (alpha) 2827 960 w (=) 3072 960 w (1.2,) 3157 960 w (radius) 3336 960 w (=) 3609 960 w (1.0) 3694 960 w (and) 3848 960 w (try) 4021 960 w (increasing) 4160 960 w (or) 4598 960 w (decreas\255) 4709 960 w (ing) 720 1080 w (the) 874 1080 w (alpha) 1022 1080 w (parameter) 1264 1080 w (to) 1688 1080 w (get) 1792 1080 w (the) 1940 1080 w (desired) 2088 1080 w (effect.) 2402 1080 w (This) 2679 1080 w (type) 2883 1080 w (of) 3081 1080 w (filter) 3190 1080 w (is) 3410 1080 w (best) 3503 1080 w (for) 3690 1080 w (filtering) 3832 1080 w (out) 4181 1080 w (dithering) 4336 1080 w (noise) 4724 1080 w (in) 4962 1080 w (both bitmap and color images.) 720 1200 w 10 /Times-Bold f (Edge enhancement. \(\2550.1 ) 720 1440 w 10 /S f (>) 1794 1440 w 10 /Times-Bold f (= alpha ) 1849 1440 w 10 /S f (>) 2196 1440 w 10 /Times-Bold f (= \2550.9\)) 2251 1440 w 10 /Times-Roman f (This) 720 1632 w (is) 930 1632 w (the) 1029 1632 w (opposite) 1183 1632 w (type) 1554 1632 w (of) 1758 1632 w (filter) 1873 1632 w (to) 2099 1632 w (the) 2210 1632 w (smoothing) 2365 1632 w (filter.) 2821 1632 w (It) 3073 1632 w (enhances) 3167 1632 w (edges.) 3565 1632 w (The) 3850 1632 w (alpha) 4038 1632 w (parameter) 4287 1632 w (controls) 4718 1632 w (the) 720 1752 w (amount) 881 1752 w (of) 1220 1752 w (edge) 1342 1752 w (enhancement,) 1569 1752 w (from) 2159 1752 w (subtle) 2392 1752 w (\(\2550.1\)) 2670 1752 w (to) 2933 1752 w (blatant) 3050 1752 w (\(\2550.9\).) 3360 1752 w (The) 3647 1752 w (radius) 3840 1752 w (parameter) 4122 1752 w (controls) 4558 1752 w (the) 4918 1752 w (effective) 720 1872 w (radius) 1095 1872 w (as) 1366 1872 w (usual,) 1476 1872 w (but) 1739 1872 w (useful) 1895 1872 w (values) 2167 1872 w (are) 2450 1872 w (between) 2599 1872 w (0.5) 2959 1872 w (and) 3112 1872 w (0.9.) 3284 1872 w (Try) 3462 1872 w (starting) 3634 1872 w (with) 3962 1872 w (values) 4168 1872 w (of) 4451 1872 w (alpha) 4562 1872 w (=) 4806 1872 w (0.3,) 4890 1872 w (radius = 0.8) 720 1992 w 10 /Times-Bold f (Combination use.) 720 2232 w 10 /Times-Roman f (The) 720 2424 w (various) 909 2424 w (modes) 1237 2424 w (of) 1532 2424 w 10 /Times-Bold f (pnmnlfilt) 1649 2424 w 10 /Times-Roman f (can) 2084 2424 w (be) 2256 2424 w (used) 2384 2424 w (one) 2601 2424 w (after) 2780 2424 w (the) 2997 2424 w (other) 3154 2424 w (to) 3394 2424 w (get) 3507 2424 w (the) 3664 2424 w (desired) 3821 2424 w (result.) 4144 2424 w (For) 4426 2424 w (instance) 4600 2424 w (to) 4962 2424 w (turn) 720 2544 w (a) 907 2544 w (monochrome) 977 2544 w (dithered) 1530 2544 w (image into a grayscale image you could try one or two passes of the smoothing) 1883 2544 w (filter,) 720 2664 w (followed) 975 2664 w (by) 1366 2664 w (a) 1502 2664 w (pass) 1582 2664 w (of) 1790 2664 w (the) 1909 2664 w (optimal) 2067 2664 w (estimation) 2409 2664 w (filter,) 2862 2664 w (then) 3117 2664 w (some) 3325 2664 w (subtle) 3572 2664 w (edge) 3847 2664 w (enhancement.) 4071 2664 w (Note) 4659 2664 w (that) 4890 2664 w (using) 720 2784 w (edge) 968 2784 w (enhancement) 1187 2784 w (is) 1744 2784 w (only) 1842 2784 w (likely) 2051 2784 w (to) 2310 2784 w (be) 2419 2784 w (useful) 2544 2784 w (after) 2819 2784 w (one) 3032 2784 w (of) 3207 2784 w (the) 3321 2784 w (non\255linear) 3473 2784 w (filters) 3913 2784 w (\(alpha) 4176 2784 w (trimmed) 4455 2784 w (mean) 4824 2784 w (or optimal estimation filter\), as edge enhancement is the direct opposite of smoothing.) 720 2904 w (For) 720 3060 w (reducing) 888 3060 w (color) 1266 3060 w (quantization) 1500 3060 w (noise) 2023 3060 w (in) 2263 3060 w (images) 2370 3060 w (\(ie.) 2682 3060 w (turning) 2841 3060 w (.gif) 3159 3060 w (files) 3324 3060 w (back) 3525 3060 w (into) 3742 3060 w (24) 3927 3060 w (bit) 4056 3060 w (files\)) 4191 3060 w (you) 4425 3060 w (could) 4604 3060 w (try) 4855 3060 w (a) 4996 3060 w (pass) 720 3180 w (of) 928 3180 w (the) 1047 3180 w (optimal) 1205 3180 w (estimation) 1547 3180 w (filter) 2000 3180 w (\(alpha) 2230 3180 w (1.2,) 2515 3180 w (radius) 2701 3180 w (1.0\),) 2981 3180 w (a) 3200 3180 w (pass) 3280 3180 w (of) 3488 3180 w (the) 3607 3180 w (median) 3765 3180 w (filter) 4095 3180 w (\(alpha) 4325 3180 w (0.5,) 4610 3180 w (radius) 4796 3180 w (0.55\),) 720 3300 w (and) 987 3300 w (possibly) 1165 3300 w (a) 1533 3300 w (pass) 1611 3300 w (of) 1817 3300 w (the) 1934 3300 w (edge) 2091 3300 w (enhancement) 2314 3300 w (filter.) 2875 3300 w (Several) 3154 3300 w (passes) 3488 3300 w (of) 3778 3300 w (the) 3896 3300 w (optimal) 4053 3300 w (estimation) 4394 3300 w (filter) 4846 3300 w (with) 720 3420 w (declining) 924 3420 w (alpha) 1322 3420 w (values) 1564 3420 w (are) 1845 3420 w (more) 1992 3420 w (effective) 2223 3420 w (than a single pass with a large alpha value.) 2597 3420 w (As usual, there is) 4352 3420 w (a tradeoff between filtering effectiveness and loosing detail. Experimentation is encouraged.) 720 3540 w 10 /Times-Bold f (References:) 720 3780 w 10 /Times-Roman f (The) 720 3972 w (alpha\255trimmed) 905 3972 w (mean) 1523 3972 w (filter) 1769 3972 w (is) 1993 3972 w (based) 2090 3972 w (on) 2347 3972 w (the) 2477 3972 w (description) 2629 3972 w (in) 3103 3972 w (IEEE) 3211 3972 w (CG&A) 3457 3972 w (May) 3776 3972 w (1990) 3989 3972 w (Page) 4220 3972 w (23) 4445 3972 w (by) 4576 3972 w (Mark) 4707 3972 w (E.) 4954 3972 w (Lee and Richard A. Redner, and has been enhanced to allow continuous alpha adjustment.) 720 4092 w (The) 720 4248 w (optimal) 903 4248 w (estimation) 1237 4248 w (filter) 1682 4248 w (is) 1905 4248 w (taken) 2001 4248 w (from) 2246 4248 w (an) 2469 4248 w (article) 2592 4248 w ("Converting) 2870 4248 w (Dithered) 3390 4248 w (Images) 3768 4248 w (Back) 4085 4248 w (to) 4319 4248 w (Gray) 4426 4248 w (Scale") 4654 4248 w (by) 4940 4248 w (Allen) 720 4368 w (Stenger,) 969 4368 w (Dr) 1326 4368 w (Dobb's) 1458 4368 w (Journal,) 1779 4368 w (November) 2125 4368 w (1992,) 2573 4368 w (and) 2825 4368 w (this) 2996 4368 w (article) 3168 4368 w (references) 3443 4368 w ("Digital) 3877 4368 w (Image) 4222 4368 w (Enhancement) 4497 4368 w (and) 720 4488 w (Noise) 894 4488 w (Filtering) 1157 4488 w (by) 1532 4488 w (Use) 1662 4488 w (of) 1847 4488 w (Local) 1960 4488 w (Statistics",) 2217 4488 w (Jong\255Sen) 2675 4488 w (Lee,) 3077 4488 w (IEEE) 3282 4488 w (Transactions) 3529 4488 w (on) 4070 4488 w (Pattern) 4201 4488 w (Analysis) 4515 4488 w (and) 4896 4488 w (Machine Intelligence, March 1980.) 720 4608 w (The edge) 720 4764 w (enhancement) 1114 4764 w (details) 1666 4764 w (are) 1953 4764 w (from) 2100 4764 w (pgmenhance,) 2320 4764 w (which) 2875 4764 w (is) 3145 4764 w (taken) 3238 4764 w (from) 3480 4764 w (Philip) 3700 4764 w (R.) 3966 4764 w (Thompson's) 4084 4764 w ("xim") 4610 4764 w (pro\255) 4874 4764 w (gram,) 720 4884 w (which) 988 4884 w (in) 1270 4884 w (turn) 1386 4884 w (took) 1585 4884 w (it) 1801 4884 w (from) 1894 4884 w (section) 2125 4884 w (6) 2445 4884 w (of) 2532 4884 w ("Digital) 2652 4884 w (Halftones) 3008 4884 w (by) 3433 4884 w (Dot) 3570 4884 w (Diffusion",) 3757 4884 w (D.) 4243 4884 w (E.) 4377 4884 w (Knuth,) 4500 4884 w (ACM) 4812 4884 w (Transaction) 720 5004 w (on) 1223 5004 w (Graphics) 1355 5004 w (Vol.) 1747 5004 w (6,) 1954 5004 w (No.) 2061 5004 w (4,) 2241 5004 w (October) 2349 5004 w (1987,) 2703 5004 w (which) 2961 5004 w (in) 3238 5004 w (turn) 3349 5004 w (got) 3543 5004 w (it) 3704 5004 w (from) 3793 5004 w (two) 4020 5004 w (1976) 4203 5004 w (papers) 4436 5004 w (by) 4729 5004 w (J.) 4862 5004 w (F.) 4959 5004 w (Jarvis et. al.) 720 5124 w 10 /Times-Bold f (SEE ALSO) 720 5364 w 10 /Times-Roman f (pgmenhance, pnmconvol, pnm) 720 5520 w 10 /Times-Bold f (AUTHOR) 720 5760 w 10 /Times-Roman f (Graeme W. Gill graeme@labtam.oz.au) 720 5916 w 10 /S1 f (________________________________________________________________________) 720 6036 w 10 /Times-Bold f (Table Of Contents) 720 6276 w 10 /LucidaSansUnicode22 f (\031) 720 6468 w 10 /Times-Roman f (NAME) 970 6468 w 10 /LucidaSansUnicode22 f (\031) 720 6624 w 10 /Times-Roman f (SYNOPSIS) 970 6624 w 10 /LucidaSansUnicode22 f (\031) 720 6780 w 10 /Times-Roman f (DESCRIPTION) 970 6780 w 10 /LucidaSansUnicode22 f (\031) 720 6936 w 10 /Times-Roman f (Alpha trimmed mean filter.\(0.0 <= alpha <= 0.5\)) 970 6936 w 10 /LucidaSansUnicode22 f (\031) 720 7092 w 10 /Times-Roman f (Optimal estimation smoothing. \(1.0 <= alpha <= 2.0\)) 970 7092 w 10 /LucidaSansUnicode22 f (\031) 720 7248 w 10 /Times-Roman f (Edge enhancement. \(\2550.1 >= alpha >= \2550.9\)) 970 7248 w cleartomark showpage saveobj restore %%EndPage: 2 2 %%Page: 3 3 /saveobj save def mark 3 pagesetup 10 /Times-Roman f (\255 3 \255) 2797 480 w 10 /LucidaSansUnicode22 f (\031) 720 840 w 10 /Times-Roman f (Combination use.) 970 840 w 10 /LucidaSansUnicode22 f (\031) 720 996 w 10 /Times-Roman f (References:) 970 996 w 10 /LucidaSansUnicode22 f (\031) 720 1152 w 10 /Times-Roman f (SEE ALSO) 970 1152 w 10 /LucidaSansUnicode22 f (\031) 720 1308 w 10 /Times-Roman f (AUTHOR) 970 1308 w cleartomark showpage saveobj restore %%EndPage: 3 3 %%Trailer done %%DocumentFonts: Times-Roman LucidaSansUnicode22 Times-Italic Times-Bold S1 S %%Pages: 3