i.colors.enhance(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

✨ i.colors.enhance ✨ (the GRASS GIS User's Manual era) 🎀

okay bestie, gather round, because this is the manual page for i.colors.enhance, and she is that girl 💅

NAME

i.colors.enhance — Performs auto-balancing of colors for RGB images. 🦋

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 🔥
  • -p — Preserve relative colors, adjust brightness only ✨
  • -r — Reset to standard color range 🔄
  • -s — Process bands serially (default: run in parallel) 🐢
  • --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

💫 DESCRIPTION 💫

i.colors.enhance auto-balances and enhances the color channels of a RGB image (e.g. from Landsat) to provide a more natural color mixture. Only the color table of each image band is modified, the base data remains untouched. 🫶 no cap, your actual pixels are safe.

The module works by calculating a histogram for each color channel and removing an adjustable amount of outliers from either end before recalibrating the color scale with r.colors. 📊✨

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. 👑

📝 NOTES 📝

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. 🔬 lowkey a vibe-check-your-own-data situation.

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. 📈💅

For quicker execution of this module on large images you can achieve largely similar results by switching to a coarser resolution before the running of the module (using g.region) and then back to the original resolution afterwards. 🏃♀️💨

🌈 EXAMPLE 🌈

North Carolina sample dataset example with Landsat data: 🛰️

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 😭

Color corrected RGB composite of Landsat ETM channels B/G/R 😍 the glow-up is REAL

🚧 TODO 🚧

The strength option requires further refinement. 🛠️ she's a work in progress, bestie.

👀 SEE ALSO 👀

  • d.rgb
  • g.region
  • i.oif
  • r.colors
  • r.composite
  • r.univar

👑 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) 🔗

Accessed: Saturday Jan 17 05:41:52 2026 ⏰

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

💖 and that's the whole page, bestie. GRASS 8.4.2, © 2003-2025 GRASS Development Team, straight outta the GRASS GIS 8.4.2 Reference Manual — go balance some colors, you absolute icon, periodt. 💅✨🌸
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