# pgmabel (1) - Linux Manuals

## pgmabel: create cross section using Abel Integration for Deconvolution

## 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 calculation 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

## HISTORY

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

## AUTHOR

Volker Schmidt (lefti [at] voyager.boerde.de)

Copyright (C) 1997-2002 German Aerospace research establishment