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RE: filmscanners: VueScan Histogram

Ed writes ...

> In a message dated 12/17/2001 10:46:16 AM EST, rarewolf@roadrunner.nf.net
> writes:
> > How is the upper histogram calculated?
>     m_hst[3][(306L*pix[0]+601L*pix[1]+117L*pix[2])>>18]++;

  at 1st guess ... it is "weighted green" ... a normalized
(30.6%RED + 60.1%GREEN + 11.7%BLUE) ...

  ... and I agree with weighted green being one of the best methods for
evaluating the "lightness" of color ... however, because for "white" and
"black", when R=G=B, I have to wonder how useful "weighted green" is for
evaluating "how many white pixels" & "how many black pixels"(???)

  (... by no means a criticism, and I thusfar like Ed's implimentation ...
but I believe how lightness is calculated is important to properly
evaluating Wp & Bp ...)

shAf  :o)


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