diff options
Diffstat (limited to 'pgmhist.html')
| -rw-r--r-- | pgmhist.html | 36 |
1 files changed, 29 insertions, 7 deletions
diff --git a/pgmhist.html b/pgmhist.html index 2f9e2f4e..9c3f03b1 100644 --- a/pgmhist.html +++ b/pgmhist.html @@ -16,6 +16,8 @@ pgmhist - print a histogram of the values in a PGM image [<b>-median</b>, <b>-quartile</b>, <b>-decile</b>] +[<b>-forensic</b>] + [<b>-machine</b>] [<I>pgmfile</I>] @@ -53,27 +55,47 @@ You must specify exactly one of the ramp type options. <p>You may specify at most one of <b>-median</b>, <b>-quartile</b>, and <b>-decile</b>. -<P>This option was new in Neptbm 10.61 (December 2012). +<P>This option was new in Netpbm 10.61 (December 2012). <DT><B>-quartile</B> <DD> -<P>This option causes <b>pgmhist</b> to print the four quartile gray value. +<P>This option causes <b>pgmhist</b> to print the four quartile gray values. <p>You may specify at most one of <b>-median</b>, <b>-quartile</b>, and <b>-decile</b>. -<P>This option was new in Neptbm 10.61 (December 2012). +<P>This option was new in Netpbm 10.61 (December 2012). <DT><B>-decile</B> <DD> -<P>This option causes <b>pgmhist</b> to print the ten decile gray value. +<P>This option causes <b>pgmhist</b> to print the ten decile gray values. <p>You may specify at most one of <b>-median</b>, <b>-quartile</b>, and <b>-decile</b>. -<P>This option was new in Neptbm 10.61 (December 2012). +<P>This option was new in Netpbm 10.61 (December 2012). + +<dt><b>-forensic</b><dd> + +<p>With this option, <b>pgmhist</b> works on images that contain invalid gray +values. Normally, like most Netpbm programs, <b>pgmhist</b> fails if it +encounters a gray value greater than the maxval that the image declares. The +presence of such a value means the image is invalid, so the pixels have no +meaning. But with <b>-forensic</b>, <b>pgmhist</b> produces a histogram +of the actual gray values without regard to maxval. It issues messages +summarizing the invalid pixels if there are any. + +<p>One use for this is to diagnose the problem that caused the invalid Netpbm +image to exist. + +<p>There is a small exception to the ability of <b>pgmhist</b> to process +invalid pixels even with <b>-forensic</b>: it can never process a gray value +greater than 65535. Note that in the rarely used Plain PGM format, it is +possible for a number greater than that to appear where a gray value belongs. + +<p>This option was new in Netpbm 10.66 (March 2014). <DT><B>-machine</B> <DD> @@ -91,12 +113,12 @@ the gray values. The line consists of two tokens separated by a space. The first is the gray value; the second is the number of pixels in the image that have that gray value. Both are decimal numbers without leading zeroes. -<P>This option was new in Neptbm 10.61 (December 2012). +<P>This option was new in Netpbm 10.61 (December 2012). </DL> -<H2 id="name">SEE ALSO</H2> +<H2 id="seealso">SEE ALSO</H2> <A HREF="pnmnorm.html">pnmnorm</A>, <A HREF="ppmhist.html">ppmhist</A> |