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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 caculation 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(1),


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


AUTHOR
       Volker Schmidt (leftiATvoyager.de)

       Copyright (C) 1997-2002 German Aerospace research establishment



netpbm documentation               June 2002            Pgmabel User Manual(0)