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


       pgmabel - create cross section using Abel Integration for Deconvolution


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

       You can abbreviate any option to its shortest unique prefix.


       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  ver-
       tical  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*fac-
       tor 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.


       -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

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

       -right Analogous to -left.

              print information about the calculation.


       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


       pnmrotate(1), pgm(1),


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


       Volker Schmidt (

       Copyright (C) 1997-2002 German Aerospace research establishment

netpbm documentation               June 2002            Pgmabel User Manual(0)

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