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Calculation of contrast-based scalefactor
8/17/93
Input: ex = picture exposure
or: Lwa = world adaptation luminance
Output: sf = scalefactor for display
adj = corresponding exposure adjustment
Optional Inputs: Ldmax = maximum display luminance
Lda = display adaptation luminance
}
Lwa = WE*.5/ex;
Ldmax = 120;
Lda = Ldmax/2;
sf = ((1.219 + Lda^.4)/(1.219 + Lwa^.4))^2.5 / Ldmax;
adj = WE*sf/ex;
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