Pgmabel User Manual(0)                                  Pgmabel User Manual(0)



NAME
       pgmabel - create cross section using Abel Integration for Deconvolution


SYNOPSIS
       pgmabel [-help] [-axis axis] [-factor factor] [-pixsize pixsize] [-left
       | -right] [-verbose] [filespec]


DESCRIPTION
       This program is part of Netpbm(1)

       pgmabel 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.  pgmabel produces as output an image of a
       cross-section of the image.

       pgmabel does the calculation by performing the Abel Integration for
       Deconvolution of an axial-symmetrical image by solving the system of
       linear equations.

       After integration, pgmabel weights all gray-values of one side by the
       surface area of the calculated ring in square pixels divided by
       4*factor multiplied by the size of one pixel (pixsize).  With the
       -verbose option, pgmabel prints the weighting factors.

       Where the calculation generates a negative result, the output is black.

       The computation is unstable against periodic structures with size 2 in
       the vertical direction.


OPTIONS
       You can abbreviate any option to its shortest unique prefix.




       -help  Prints a help message.


       -axis axis
              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.


       -factor factor
              User defined factor for enhancement of the output.  Use a factor
              less than 1 for decreasing gary values.  Default is 1.0.


       -pixsize pixsize
              The size of a pixel for getting scale invariant.  Default is
              0.1.


       -left  Calculate only the left side of the image.  You cannot specify
              both left and right.


       -right Analogous to -left.


       -verbose
              print information about the calculation.




EXAMPLE
       Rotate a PGM image to get an image with a vertical axis of symmetry,
       then calculate the cross section:

           pnmrotate 90 file.pgm | pgmabel -axis 140 >cross_section.pgm




SEE ALSO
       pnmrotate(1) , pgm(5) ,


HISTORY
       This program was added to Netpbm in Release 10.3 (June 2002).


AUTHOR
       Volker Schmidt (lefti@voyager.boerde.de)

       Copyright (C) 1997-2002 German Aerospace research establishment

netpbm documentation               June 2002            Pgmabel User Manual(0)