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Re: [Color balance] The operation behind...

Posted by Herbie on Apr 14, 2021; 12:06pm
URL: http://imagej.273.s1.nabble.com/Color-balance-The-operation-behind-tp5024606p5024607.html

Greetings,

definitely not my field, but it may help to have a look at the source code:
<https://imagej.nih.gov/ij/source/ij/plugin/frame/ContrastAdjuster.java>

Regards

Herbie

:::::::::::::::::::::::::::::::::
Am 14.04.21 um 11:27 schrieb Kost:

> Hi everybody,
>
> Today I was trying to explain the color balance correction for a RGB images
> and got stuck on understanding what operation ImageJ do when using the tool
> Image > Adjust > Color balance in a specific channel.
>
> I was reading the mathematics of color balance in Wikipedia but so far
> without success.
> https://en.wikipedia.org/wiki/Color_balance#Mathematics_of_color_balance
>
> To try to understand, I opened one image and then looked and one and only
> pixel.
> When not changing the color range in the red channel (original image), the
> values in the channels were (168, 075, 095)
> After selecting the minimum in the histogram for the channel red from 50 to
> 255 the values changed to (147, 075, 095) .
>
>
> To wrap up:*
> Original pixel value with R[0-255] = (168, 075, 095)
> Edited pixel value with R[50-255] = (147, 075, 095)
>
>
> How did ImageJ went from 168 to 147?
>
>
>
> Thanks in advance for your help :)
> Kind regards,
> Kornelius
>
>
>
> *Explanation of the notation:
> The intensity in each channel are between parentheses (R,G,B) and the
> selected range for a color channel is reported between square brackets; i.e.
> original color range in the red channel = R[0-255]
>
>
>
> --
> Sent from: http://imagej.1557.x6.nabble.com/
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

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