i.colors.enhance(1grass)

💖 i.colors.enhance — the GRASS User's Manual glow-up 💖

okay bestie, pull up a chair 🫶 this is i.colors.enhance, straight out of the GRASS User's Manual, and it's literally here to do auto-balancing of colors for RGB images. no cap.

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✨ NAME ✨

i.colors.enhance — performs auto-balancing of colors for RGB images. it's giving makeup artist for your satellite data 💅

🏷️ KEYWORDS 🏷️

imagery, RGB, satellite, colors 🌈

📜 SYNOPSIS 📜

i.colors.enhance
i.colors.enhance --help
i.colors.enhance [-fprs] red=name green=name blue=name  [strength=float]
[--help]  [--verbose]  [--quiet]  [--ui]

🚩 Flags 🚩

• -f — extend colors to full range of data on each channel. go big or go home ✨
• -p — preserve relative colors, adjust brightness only. keep the vibe, just fix the lighting 🎀
• -r — reset to standard color range. factory reset era 🙈
• -s — process bands serially (default: run in parallel). one at a time, queen, no multitasking 💀
• --help — print usage summary 📖
• --verbose — verbose module output 🗣️
• --quiet — quiet module output 🤫
• --ui — force launching GUI dialog 🖥️

🎛️ Parameters 🎛️

• red=name [required] — name of red channel ❤️
• green=name [required] — name of green channel 💚
• blue=name [required] — name of blue channel 💙
• strength=float — cropping intensity (upper brightness level)
  • Options: 0-100
  • Default: 98

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🌸 DESCRIPTION 🌸

so what does i.colors.enhance actually do? bestie, it auto-balances and enhances the color channels of a RGB image (think e.g. from Landsat) so you get a way more natural color mixture. the way that it only touches the color table of each image band and leaves the base data completely untouched? obsessed. 🫶 your actual data is safe, periodt.

here's the secret sauce: the module calculates a histogram for each color channel, then removes an adjustable amount of outliers from either end, and then recalibrates the color scale with r.colors. iconic behavior.

it will work with any 8-bit RGB imagery set, and the script is easily modified to work with other datasets of greater band-depth. flexible queen 👑

📝 NOTES 📝

ngl, depending on the image, it may or may not be advantageous to use the -p flag to preserve the relative color scaling. you will have to experiment with the different options to find a setting that works best for your particular imagery. it's giving trial and error, and that's okay 💅

the strength option should generally be set in the 90-99 range. the lower the number, the more saturated the image becomes. it represents the percentage cut-off for the top end of the color histogram curve. the lower end is fixed at 2% of the area under the curve. so like, strength = top-end drama, 2% = bottom-end fixed, iykyk 📊

want faster execution on large images? bestie, for quicker execution of this module on large images you can achieve largely similar results by switching to a coarser resolution before running the module (using g.region) and then switching back to the original resolution afterwards. lowkey genius ⚡

🧪 EXAMPLE 🧪

North Carolina sample dataset example with Landsat data, let's goooo 🛰️

g.region raster=lsat7_2002_10 -p
d.rgb blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30
d.barscale at=55.3125,93.125 bcolor=white text_pos=over
i.colors.enhance blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30 strength=95
d.rgb blue=lsat7_2002_10 green=lsat7_2002_20 red=lsat7_2002_30
d.barscale at=55.3125,93.125 bcolor=white text_pos=over

• Uncorrected RGB composite of Landsat ETM channels B/G/R 😭 (before)
• Color corrected RGB composite of Landsat ETM channels B/G/R 🔥 (after — ate)

🚧 TODO 🚧

the strength option requires further refinement. character development arc pending 🧚

👀 SEE ALSO 👀

d.rgb, g.region, i.oif, r.colors, r.composite, r.univar — go read those too, bestie, they're all part of the squad 💜

👑 AUTHORS 👑

• Markus Neteler, Trento, Italy
• M. Hamish Bowman, Dept. Marine Science, Otago University, New Zealand

💾 SOURCE CODE 💾

Available at: i.colors.enhance source code (history)

Latest change: Sunday Oct 19 00:09:21 2025 in commit: 5f20320dc7ec7bc36d9a8f45414d34349e1d9500

Main index | Imagery index | Topics index | Keywords index | Graphical index | Full index

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and that's the whole page, bestie 🎀 no detail left behind, all facts intact, vibe immaculate. this was i.colors.enhance from the GRASS 8.5.0 Reference Manual, © 2003-2026 GRASS Development Team, running on GRASS 8.5.0 — slay, stay colorful, and remember: only the color table gets modified 💖✨🦋