<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD><title>Pgmabel User Manual</title></HEAD> <BODY> <H1>pgmabel</H1> Updated: June 2002 <BR> <A HREF="#index">Table Of Contents</A> <A NAME="lbAB"> </A> <H2>NAME</H2> pgmabel - create cross section using Abel Integration for Deconvolution <A NAME="lbAC"> </A> <H2>SYNOPSIS</H2> <b>pgmabel</b> [<b>-help</b>] [<b>-axis</b> <i>axis</i>] [<b>-factor</b> <i>factor</i>] [<b>-pixsize</b> <i>pixsize</i>] [<b>-left</b> | <b>-right</b>] [<b>-verbose</b>] [<I>filespec</I>] <A NAME="lbAD"> </A> <H2>DESCRIPTION</H2> <p>This program is part of <a href="index.html">Netpbm</a>. <p><b>pgmabel</b> reads as input a PGM image, which it assumes to be an image of a rotational symmetric transparent object. The image must have a vertical symmetry axis. <b>pgmabel</b> produces as output an image of a cross-section of the image. <b>pgmabel</b> does the calculation by performing the Abel Integration for Deconvolution of an axial-symmetrical image by solving the system of linear equations. After integration, <b>pgmabel</b> weights all gray-values of one side by the surface area of the calculated ring in square pixels divided by 4*<i>factor</i> multiplied by the size of one pixel (<i>pixsize</i>). With the <b>-verbose</b> option, <b>pgmabel</b> prints the weighting factors. <P>Where the caculation generates a negative result, the output is black. <P>The computation is unstable against periodic structures with size 2 in the vertical direction. <A NAME="lbAE"> </A> <H2>OPTIONS</H2> <P>You can abbreviate any option to its shortest unique prefix. <DL COMPACT> <dt><b>-help</b> <dd>Prints a help message. <dt><b>-axis</b> <i>axis</i> <dd>Position of the axis of symmetry in the image in pixels from the left edge of the image. Default is the center of the image. <dt><b>-factor</b> <i>factor</i> <dd>User defined factor for enhancement of the output. Use a <i>factor</i> less than 1 for decreasing gary values. Default is 1.0. <dt><b>-pixsize</b> <i>pixsize</i> <dd>The size of a pixel for getting scale invariant. Default is 0.1. <dt><b>-left</b> Calculate only the left side of the image. You cannot specify both <b>left</b> and <b>right</b>. <dt><b>-right</b> Analogous to <b>-left</b>. <dt><b>-verbose</b> <dd>print information about the calculation. </DL> <A NAME="example"> </A> <h2>EXAMPLE</h2> <p>Rotate a PGM image to get an image with a vertical axis of symmetry, then calculate the cross section: <pre> pnmrotate 90 file.pgm | pgmabel -axis 140 >cross_section.pgm </pre> <A NAME="lbAF"> </A> <H2>SEE ALSO</H2> <B><A HREF="pnmrotate.html">pnmrotate</A></B>, <B><A HREF="pgm.html">pgm</A></B>, <A NAME="history"> </A> <H2>HISTORY</H2> <p>This program was added to Netpbm in Release 10.3 (June 2002). <A NAME="author"></a> <h2>AUTHOR</h2> <p>Volker Schmidt (lefti@voyager.boerde.de) <p>Copyright (C) 1997-2002 German Aerospace research establishment <HR> <A NAME="index"> </A> <H2>Table Of Contents</H2> <UL> <LI><A HREF="#lbAB">NAME</A> <LI><A HREF="#lbAC">SYNOPSIS</A> <LI><A HREF="#lbAD">DESCRIPTION</A> <LI><A HREF="#lbAE">OPTIONS</A> <LI><A HREF="#example">EXAMPLE</A> <LI><A HREF="#lbAF">SEE ALSO</A> <LI><A HREF="#history">HISTORY</A> <LI><A HREF="#author">AUTHOR</A> </UL> </BODY> </HTML>