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Barco - RHDM-2301 - User manual 155
Video signal processing
5.4 Effective gamma
The Rec.709 encoding equation assumes a linear tail and a power function with an exponent 0.45.
However, because of the linear offset and scaling, it is not correct to state that the Rec.709
encoding equation is described by a gamma of 0.45. The Rec.709 encoding equation is best fitted
with a pure power function with an exponent 0.52 (see figure below). We call this “best fit” the
“
effective gamma
”
.
Figure 55: The Rec.709 encoding equation fitted with a power function
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