An appropriate correction quantity is obtained for a video luminance signal
on an individual video basis with a characteristic value, like the maximum
or average value, of the luminance signal taken into account, thereby
performing gray scale correction more effectively. A dynamic gamma
correction apparatus for performing a correction on a video luminance
signal includes: a correction start point control section for obtaining a
correction start point, which is a lower limit of a given correction
range, in accordance with a characteristic value of the luminance signal;
a gamma correction quantity calculating section for obtaining a
provisional correction quantity for the luminance signal to be corrected
using the correction start point and the luminance signal; a gamma
correction gain control section for obtaining a gain for the provisional
correction quantity in accordance with the characteristic value of the
luminance signal; a multiplier for obtaining a product of the provisional
correction quantity and the gain as a gamma correction quantity; and an
adder for obtaining a sum of the luminance signal and the gamma correction
quantity and outputting the sum. The correction start point and the gain
for the provisional correction quantity are controllable in accordance
with the characteristic value of the luminance signal. Thus, an
appropriate gamma correction quantity can be obtained as a final
correction quantity.