TCA_CORRECT("1")

✨ NAME ✨

okay so this is tca_correct from the HUGIN gang — it calculates transverse chromatic aberration 💅 no cap, that's the whole job.

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🎀 SYNOPSIS 🎀

tca_correct [options] inputfile

bestie listen, <inputfile> is not one file, it's the base name for 4 image files, and you gotta know all of them:

• <inputfile> — the colour file you're computing TCA parameters from 🌈
• red_<inputfile> — the red channel of <inputfile>
• green_<inputfile> — the green channel of <inputfile>
• blue_<inputfile> — the blue channel of <inputfile>

k so the channel images must be colour images with 3 identical channels, fr fr, that's non-negotiable.

but like… if you pass any of -R, -G, or -B, then that file name gets used instead of the derived name. so you can override the whole name situation. iconic behaviour honestly 🫶

Output: commandline arguments for fulla 💖

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🦋 DESCRIPTION 🦋

so what does it actually do? it generates fulla command-line parameters for correction of transverse chromatic aberration (TCA) from sample photos. that's the vibe.

and if you wanna know what makes a good sample photo — the dream scenario would be one with a lot of contrast over the entire image area, little saturated colour, and no blown highlights. lowkey picky but honestly she's right 😭

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💜 OPTIONS 💜

• -h — display help, the classic. always start here bestie 🎀
• -l — the input file is a PTO file instead of an image, plot twist
• -m method — optimization method (0 normal, 1 newfit). pick your fighter ✨
• -o optvars — string of variables to optimize ("abcvde"). yes that exact string, character for character 🔥
• -r — reset values (this will zero a,b,c,d,e params and set v to 10) — and heads up, this only makes sense with the -l option ⚠️
• -s <scale> — scale for corner detection
• -n <number> — number of points per grid cell (default: 10)
• -g <number> — divide image in <number>x*<number>* grid cells (default: 10)
• -t num — remove all control points with an error higher than num pixels (default: 1.5)
• -v — verbose. she talks more. we love her for it 💬
• --save-into-database — saves the tca data into Hugin lens database 👑
• -w filename — write PTO file
• -R <r> — use this file as red channel
• -G <g> — use this file as green channel
• -B <b> — use this file as blue channel

quick reminder: those -R / -G / -B ones are the file names that replace the derived red_ / green_ / blue_ names — don't forget or you'll be confused later, iykyk 🙈

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🌸 AUTHORS 🌸

written by Pablo d'Angelo and others 💖 absolute legends, all of them.

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and that's the tea, bestie 🍓 this was Version: 2025.0.1, dated 2026-09-22 — go forth and de-aberrate those transverses 💅✨