[Insight-users] Rgb image bright and contrast adjust

[Dan Mueller]

Hi Liqin,

According to Wikipedia (reliability questionable), GIMP uses the
following formula:
    http://en.wikipedia.org/wiki/Image_editing

if (brightness < 0.0)  value = value * ( 1.0 + brightness);
else value = value + ((1 - value) * brightness);
value = (value - 0.5) * (tan ((contrast + 1) * PI/4) ) + 0.5;

where value is the input color value in the 0..1 range and brightness
and contrast are in the -1..1 range.

I have implemented this formula in my own applications, and it seems
to work quite well.

HTH

Cheers, Dan

On 16 September 2011 00:00, Wang, Liqin <Wang.Liqin at mayo.edu> wrote:
> Dear All,
>
> I am working at Mayo clinic for some clinical image applications. Now we
> need to adjust  RGB image bright and contrast.
> Could you please point some reference as how to adjust rgb image bright and
> contrast?
>
> Thanks,
>
> Liqin
>
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