Re: 2 degree vs. 10 degree
Re: 2 degree vs. 10 degree
- Subject: Re: 2 degree vs. 10 degree
- From: "Bruce J. Lindbloom" <email@hidden>
- Date: Mon, 10 Feb 2003 14:29:22 -0600
Robin Myers wrote:
>
The 2-degree CIE Standard Observer was based on 2-degree field of view
>
experiments. These experiments use the foveal region of the eye which
>
has less of a blue-violet response than the surrounding retinal region
>
primarily due to the macula, a yellow filter in front of the fovea which
>
protects it from shortwave UV.
>
>
When observing colors that occupy a larger field of view than about 4
>
degrees, there is increased sensitivity to the blue-violet region of the
>
spectrum. So, the CIE adopted the 10-degree Standard Observer in 1964
>
to be used for larger field of view color comparisons.
Thanks for that great explanation. You can graphically view what Robin is
talking about here:
<
http://www.brucelindbloom.com/CIESpectralCalculator.html>, where you'll see
the increased response in the blue region (< 500 nm) when comparing the
2-degree observer against the 10-degree observer.
>
I believe the reason for the ICC adopting the 2-degree observer is
>
fairly valid. In most image processing, large fields of view are seldom
>
encountered.
I agree. The 10-degree standard observer is used in other industries making
such things as paint, wallpaper, fabric, carpeting and tiles where a color
sample might be represented by an entire floor or wall of a room.
--
Bruce J. Lindbloom
email@hidden
http://www.brucelindbloom.com
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