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diff --git a/pnmhisteq.html b/pnmhisteq.html index d73857c6..2e7ccfd0 100644 --- a/pnmhisteq.html +++ b/pnmhisteq.html @@ -2,7 +2,7 @@ <HTML><HEAD><TITLE>Pnmhisteq User Manual</TITLE></HEAD> <BODY> <H1>pnmhisteq</H1> -Updated: 02 February 2010 +Updated: 22 March 2015 <BR> <A HREF="#index">Table Of Contents</A> @@ -16,6 +16,9 @@ pnmhisteq - histogram equalize a PNM image [<B>-gray</B>] +[<B>-noblack</B>] +[<B>-nowhite</B>] + [<B>-rmap</B> <I>pgmfile</I>] [<B>-wmap</B> <I>pgmfile</I>] @@ -111,6 +114,27 @@ annotations you don't want modified. Weather satellite images that show continent outlines in color are best processed using this option. The option has no effect when the input is a graymap. +<DT><B>-noblack</B> + +<dd>Do not include black pixels in the equalization. The black pixels in the +output are exactly the black pixels in the input and the number of black +pixels does not affect the color of any other pixels. + +<p>Sometimes, black isn't as much a color as a background or annotation for +the real colors, so you want to treat it specially this way. Think of a +picture of stars, which is nearly all black, but with lots of stars of +different brightness. You want to change the brightnesses of the stars to +maximize contrast between them, but if you considered the blackness to be +significant, all the stars would end up close to full white. + +<p>This option was new in Netpbm 10.70 (March 2015). + +<DT><B>-nowhite</B> + +<p>Same as <b>-noblack</b>, but for the white pixels. + +<p>This option was new in Netpbm 10.70 (March 2015). + <DT><B>-rmap</B> <I>mapfile</I> <DD>Process the image using the luminosity map specified by the PGM |