what RGB is blue?
Mark Schonewille
m.schonewille at economy-x-talk.com
Fri Jul 1 05:52:45 EDT 2011
Tiemo,
The distance between any colour (1) and a colour chosen by you (2; e.g. r=0, g=0, b=255) can be calculated as
sqrt((r1-r2)^2+(g1-g2)^2+(b1-b2)^2) <= T
where T is a threshold between 0 and 442 set by you. Change the colour of the background pixel whenever the distance between the colour of that pixel and your selected colour is less than the threshold.
I use this technique in Color Converter http://www.color-converter.com
--
Best regards,
Mark Schonewille
Economy-x-Talk Consulting and Software Engineering
Homepage: http://economy-x-talk.com
Twitter: http://twitter.com/xtalkprogrammer
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New: Download the Installer Maker Plugin 1.6 for LiveCode here http://qery.us/ce
On 1 jul 2011, at 11:39, Tiemo Hollmann TB wrote:
> Hello,
>
> I am taking the mousecolor at different points from an image by script (not
> by clicking). I would like to analyse if the color I've taken is a "kind of
> blue", or another color. I want to change the backgroundcolor of an image.
> The background is always blue, but different blues and changing over the
> background. So what I want to do is to verify, what is background and what
> is foreground of my image.
>
> 100% pure blue would be 0,0,255. But for a human being 25,75,130 (greyblue)
> is also still blue, but 240,20,180 is pink, though the third RGB value is
> higher as in my greyblue.
>
> So I can't just check only the third RGB value, neither the sum or cross
> total. Has anybody ever heard, if you can define at all by math "what is
> blue"?
>
> Any color specialist around here?
>
> Tiemo
>
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