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tldr/pages/common/pnmnorm.md
Juri Dispan 95e6753d3e
pnmmargin, pnmmontage, pnmnlfilt, pnmnorm, pnmpad, pnmpaste: add pages (#12187) 
* pnmmargin, pnmmontage, pnmnlfilt, pnmnorm, pnmpad, pnmpaste: add pages

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Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>
Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>
2024-02-09 19:23:54 +05:30

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pnmnorm

Normalize the contrast in a PNM image. See also: pnmhisteq. More information: https://netpbm.sourceforge.net/doc/pnmnorm.html.

  • Force the brightest pixels to be white, the darkest pixels to be black and spread out the ones in between linearly:

pnmnorm {{path/to/image.pnm}} > {{path/to/output.pnm}}

  • Force the brightest pixels to be white, the darkest pixels to be black and spread out the ones in between quadratically such that pixels with a brightness of n become 50 % bright:

pnmnorm -midvalue {{n}} {{path/to/image.pnm}} > {{path/to/output.pnm}}

  • Keep the pixels' hue, only modify the brightness:

pnmnorm -keephues {{path/to/image.pnm}} > {{path/to/output.pnm}}

  • Specify a method to calculate a pixel's brightness:

pnmnorm -{{luminosity|colorvalue|saturation}} {{path/to/image.pnm}} > {{path/to/output.pnm}}