Re: [ft-devel] gamma correction demo images

[Alexei Podtelezhnikov]

On Fri, Nov 20, 2015 at 2:46 PM, Nikolaus Waxweiler <address@hidden> wrote:
>> The filter is color-balanced, but not normalized. Values above 0x100
>> will have to be clamped and this non-linearity causes distortion and
>> adds to color fringing. Stem darkening is the better way to increase
>> contrast.
>
>
> So I tried to find two values that sum to 0x100:
>
>>>> def f(a,c):
> ...  return [a - c, a + c, 2 * a, a + c, a - c]

I did some experimentation with my crazy patterns. I firmly believe
now that simple box filter aka FT_LCD_FILTER_LIGHT is not just good
but in fact the best in reducing color fringes IFF used with correct
gamma. All color-balances filters with gamma eliminate color fringes
completely, but the box filter is obviously the least blurry of them
all. So I reached the same conclusion as this paper:
http://scien.stanford.edu/jfsite/Papers/ImageRendering/Displays/Xu_Farrell_Matskewich_Wandell_final.pdf
. Some day soon I will write a blog about the details of my
experiments.