09-14-2012, 09:22 PM
[quote name='olegk' timestamp='1347626225' post='20103']
Is it possible to compute color temperature given the three raw-photo color multipliers?
(The question comes from an effort to design another approach for underwater color balancing.)
Thanks,
Oleg.
[/quote]
well you need a white card or something similar to shoot against. Standard color meters have a white diffuser in front of them when you measure incident light.
If you don't have a white reference, how should the camera know whether you point it at some red, green, blue etc. and deduce the color temperature from it?
I guess a piece of white cloth you wrap around the lens dome could do it?
If a scene has decent representations of all colors, you can of course just look at the RGB histogram, and push the red and green channels, but that's more like guesswork.
Is it possible to compute color temperature given the three raw-photo color multipliers?
(The question comes from an effort to design another approach for underwater color balancing.)
Thanks,
Oleg.
[/quote]
well you need a white card or something similar to shoot against. Standard color meters have a white diffuser in front of them when you measure incident light.
If you don't have a white reference, how should the camera know whether you point it at some red, green, blue etc. and deduce the color temperature from it?
I guess a piece of white cloth you wrap around the lens dome could do it?
If a scene has decent representations of all colors, you can of course just look at the RGB histogram, and push the red and green channels, but that's more like guesswork.