white efficacy in radiance



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white efficacy in radiance

Postby dolphin_24 » Thu, 17 Mar 2005 09:24:10 GMT

i'm trying to implement the tone mapping algorithm used in radiance.
looking at the source code of radiance (color.h), it calculates the
luminance as:
Luminance(col) = WHITEEFFICACY * bright(col);
where bright(col) is the y chromacicity component and WHITEEFFICACY =
i'm trying to figure out where that value comes from, i would expect it
to be 683.0 wich is the maximum efficacy (reached for 555nm
does anybody have any idea how this value (179) was calculated?


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