PGMABEL(1)

📦
version 11.13.03 · 4 versions
, in debian bookworm, debian trixie, ubuntu noble, ubuntu resolute, ubuntu stonking

✨ Pgmabel User Manual — section (1), General Commands Manual ✨

okay bestie, pull up a chair 🪑 because we're about to talk about pgmabel, and she is that girl. this is part of the Netpbm family, and she makes cross sections. no cap.

🌸 NAME 🌸

pgmabel — create cross section using Abel Integration for Deconvolution 💅

🎀 SYNOPSIS 🎀

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

🦋 DESCRIPTION 🦋

so. this program is part of Netpbm(1), obviously. 💖

pgmabel reads a PGM image as input, and it assumes — literally assumes, bestie — that this image is a picture of a rotational symmetric transparent object. the image has to have a vertical symmetry axis, no exceptions. and then pgmabel produces, as output, an image of a cross-section of that image.

how does she do it? pgmabel does the calculation by performing the Abel Integration for Deconvolution of an axial-symmetrical image, by solving the system of linear equations. it's giving math girlie and honestly we respect it 😭✨

after the 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). and if you turn on -verbose, pgmabel prints out those weighting factors for you. so helpful. 🫶

⚠️ real talk: where the calculation generates a negative result, the output is black. that's just how it is.
💀 also important: the computation is unstable against periodic structures with size 2 in the vertical direction. so like, watch out for that. not me warning you about your periodic structures.

💅 OPTIONS 💅

in addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options), pgmabel recognizes the following command line options:

pro tip: you can abbreviate any option to its shortest unique prefix. yes bestie, she's flexible like that. 💁‍♀️

  • -help — Prints a help message. a little "here's how i work" moment, we love a self-aware icon 👑
  • -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. (yes, the original says "gary". we keep the typo, it's canon, it's hers. 💖)
  • -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. pick a lane, bestie 🚫
  • -right — Analogous to -left. mirrored queen 🪞
  • -verbose — print information about the calculation. she's gonna tell you everything. 😭

🌈 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

look at that pipeline. ate. 🔥

⭐ SEE ALSO ⭐

pnmrotate(1), pgm(1),

🧚 HISTORY 🧚

This program was added to Netpbm in Release 10.3 (June 2002). a vintage icon, honestly. she's been slaying since 2002. 💜

👑 AUTHOR 👑

Volker Schmidt (lefti@voyager.boerde.de)

Copyright (C) 1997-2002 German Aerospace research establishment 🚀

💌 DOCUMENT SOURCE 💌

This manual page was generated by the Netpbm tool makeman from HTML source. The master documentation is at

http://netpbm.sourceforge.net/doc/pgmabel.html

and that's a wrap 🎬 netpbm documentation, June 2002 — periodt, bestie. go make some cross sections. 🍓💖

📦 where this page comes from