tion


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


DESCRIPTION
This program is part of Netpbm.

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.


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




-help Prints a help message.


-axis axis


-factor factor


-pixsize pixsize


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


-right Analogous to -left.


-verbose




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, pgm,


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