Gamma correction
Displayed light intensity is nonlinearly related to the actual intensity following the Gamma rule
g
=
a
f
r
g = af^r
Gamma correction pre-compensates this nonlinearity inside the camera
h
=
f
1
/
r
h= f^{1/r}
g
=
a
h
r
=
a
f
g=ah^r=af
Gamma value depends on the display device, typically gamma~2.2