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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
| commit | 1017cbebe5d5edd859e0fddad0a8600f509f4821 (patch) | |
| tree | 78bdf336648566f7a7d55f42837357dea3dd674c /jpeg2ktopam.html | |
| parent | 16f2ac126651015a376eba864a3a35f738b0b25a (diff) | |
| download | netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.gz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.xz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.zip | |
Place user guide into Subversion repository
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@181 9d0c8265-081b-0410-96cb-a4ca84ce46f8
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diff --git a/jpeg2ktopam.html b/jpeg2ktopam.html new file mode 100644 index 00000000..1c3104da --- /dev/null +++ b/jpeg2ktopam.html @@ -0,0 +1,149 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML><HEAD><TITLE>Jpeg2ktopam User Manual</TITLE></HEAD> +<BODY> +<H1>Jpeg2ktopam</H1> +Updated: 27 October 2002 +<BR> +<A HREF="#index">Table Of Contents</A> + +<H2>NAME</H2> +jpeg2ktopam - convert JPEG-2000 code stream to PAM/PNM + +<A NAME="synopsis"> </A> +<H2>SYNOPSIS</H2> + +<B>jpeg2ktopam</B> +[<B>-verbose</B>] +[<B>-debuglevel=</B><I>number</I>] +<I>filename</I> + +<?makeman .SH OPTION USAGE ?> + +<p>Minimum unique abbreviation of option is acceptable. You may use double +hyphens instead of single hyphen to denote options. You may use white +space in place of the equals sign to separate an option name from its value. + +<A NAME="description"> </A> +<H2>DESCRIPTION</H2> + +<p>This program is part of <a href="index.html">Netpbm</a>. + +<P><B>jpeg2ktopam</b> converts the named JPEG-2000 code stream file, +or Standard Input if no file is named, to a PBM, PGM, PPM, or PAM +file on Standard Output. + +<P>The JPEG-2000 specification specifies two different formats: JP2 +and JPEG-2000 code stream (JPC). JP2 represents a visual image quite +specifically, whereas JPC is a more or less arbitrary array of +codes. JP2 images are a subset of JPC images. <b>jpeg2ktopam</b> +converts any JPC image. If the color space identified in the image is +grayscale (JAS_IMAGE_CS_GRAY), <B>jpeg2ktopam</b> generates a PGM +image, unless the image contains only one bit per pixel, in which case +<b>jpeg2ktopam</b> generates PBM. If the color space is RGB +(JAS_IMAGE_CS_RGB), <b>jpeg2ktopam</b> generates a PPM image. If the +input image is anything else, <b>jpeg2ktopam</b> generates a PAM image +with no tuple type identified. + +<P>In the PGM and PPM cases, <b>jpeg2ktopam</b> assumes the intensity +values in the input image have the same meaning as for PGM and PPM. +One thing that implies is the ITU-R Recommendation BT.709 color space, +which means the assumption is false for JP2 input. JP2 input uses +SRGB color encoding. So if you use <b>jpeg2ktopam</b> to convert a +JP2 image to PPM, it changes the visual image (slightly) -- the colors +in the output are not the same as in the input. + +<p>In the PAM image, the output samples are numerically identical to +the input samples. If the input samples are signed, they are +represented in two's complement form in the output (because PAM +samples are always unsigned). The PAM plane numbers are identical to +the JPC component numbers. + +<p>A JPC image has a "precision," which is the number of bits used for +each code (in Netpbm lingo, "sample"). Actually, each component has a +separate precision. The maxval of a PGM, PPM, or PAM output is the +largest number you can represent in the JPC precision of the JPC +component with the greatest precision. The samples in all components are +scaled to that maxval. So if the red component has a precision of 4 bits +and the green component has a precision of 6 bits, the maxval is 63 and +the red component codes from the JPC image are multiplied by 63/15 to +generate the output samples. + +<P><b>jpeg2ktopam</b> interprets the JPC input with the <a +href="http://www.ece.uvic.ca/~mdadams/jasper/">Jasper JPEG-2000 +library</a>. See documentation of the library for details on what +<b>jpeg2ktopam</b> handles. Note that the Jasper library contains +facilities for writing PNM images, but <b>jpeg2ktopam</b> does not use +those. It uses the Netpbm library instead. Note that the makers of +the Jasper library write it "JasPer," but Netpbm documentation follows +standard American English typography rules, which don't allow that +kind of capitalization. + +<P>Use <b>pamtojpeg2k</b> to convert in the other direction. + +<p>The program <b>jasper</b>, which is packaged with the Jasper +JPEG-2000 library, also converts between JPEG-2000 and PNM formats. +Because it's packaged with the library, it may exploit it better, +especially recently added features. However, since it does not use the +Netpbm library to read and write the Netpbm formats, it doesn't do as +good a job on that side. + +<A NAME="options"> </A> +<H2>OPTIONS</H2> + +<DL COMPACT> + +<DT><B>-verbose</b> + +<DD>This option causes <b>jpeg2ktopam</b> to issue informational +messages about the conversion process. + +<DT><B>-debuglevel</b>=<i>number</i> + +<DD>This option controls debug messages from the Jasper library. +<b>jpeg2ktopam</b> passes <i>number</i> as the debug level to the Jasper +JPC decoder. + +</DL> + +<A NAME="examples"> </A> +<H2>EXAMPLES</H2> + +<pre> + jpeg2ktopam myimg.jpc >myimg.ppm +</pre> + + +<A NAME="jpeg2000"> </A> +<H2>ABOUT JPEG-2000</H2> + +<p>See <a href="pamtojpeg2k.html">the <b>pamtojpeg2k</b> manual</a> +for general information on JPEG-2000 compression and the +JPEG-2000 formats. + + + +<A NAME="seealso"> </A> +<H2>SEE ALSO</H2> + +<B><A HREF="pamtojpeg2k.html">jpctopam</A></B>, +<B><A HREF="jpegtopnm.html">pnmtopeg</A></B>, +<B><A HREF="ppm.html">ppm</A></B>, +<B><A HREF="pgm.html">pgm</A></B>, +<B><A HREF="pbm.html">pbm</A></B>, +<B><A HREF="pam.html">pam</A></B>, + +<H2>History</H2> + +<p><b>jpeg2ktopam</b> was added to Netpbm in Release 10.12 (November 2002). + +<HR> +<A NAME="index"> </A><H2>Table Of Contents</H2> +<UL> +<LI><A HREF="#synopsis">SYNOPSIS</A> +<LI><A HREF="#description">DESCRIPTION</A> +<LI><A HREF="#options">OPTIONS</A> +<LI><A HREF="#examples">EXAMPLES</A> +<LI><A HREF="#seealso">SEE ALSO</A> +</UL> +</BODY> +</HTML> |