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



Table Of Contents


NAME
       pgmabel  -  create  cross section using Abel Integration
       for Deconvolution


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

       You  can  abbreviate  any  option to its shortest unique
       prefix.


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, pgma-
       bel 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
       -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  out-
              put.   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 estab-
       lishment



netpbm documentation       June 2002     Pgmabel User Manual(0)
