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

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common  Options  ⟨index.html#commonoptions⟩  ),  pgmabel recognizes the following command
       line 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(1),

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

DOCUMENT SOURCE

       This  manual page was generated by the Netpbm tool 'makeman' from HTML source.  The master
       documentation is at

              http://netpbm.sourceforge.net/doc/pgmabel.html