pgmabel (1) - Linux Man Pages
pgmabel: create cross section using Abel Integration for Deconvolution
pgmabel [-help] [-axis axis] [-factor factor] [-pixsize pixsize] [-left | -right] [-verbose] [filespec]
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.
You can abbreviate any option to its shortest unique prefix.
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.
Calculate only the left side of the image. You cannot specify both
left and 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
This program was added to Netpbm in Release 10.3 (June 2002).
Volker Schmidt (lefti [at] voyager.boerde.de)
Copyright (C) 1997-2002 German Aerospace research establishment