[Sidefx-houdini-list] COPS - Average Colour Luminance in Image

Mark Alexander malexander at sidefx.com
Fri Apr 20 16:23:09 EDT 2007

> and this has brought the result within a decent range.
> (The result is 3.05 for a white image)
> - I'm now multiplying by a 'magic' number 
> to get the results between 0 and 1

Ah, right. I forgot to mention you should run it through a Mono COP 
first to change RGB -> lum, and then just read the Red channel into 
CHOPs. It's 3x higher than normal because of the 3 RGB channels. Sorry, 
forgot about that :) At least that should reduce the 0.05 error to 
around ~0.01, which is probably acceptable.


More information about the Sidefx-houdini-list mailing list