gamma correction

In video, the insertion of a nonlinear output-input characteristic for the purpose of changing the system transfer characteristic. [IEEE 100] Note: Historically, gamma correction was a precompensation applied to the video signal at the camera to correct for the nonlinearities of the CRT (i.e., the power function of the electron gun) and, as such, it was the inverse of the electron gun function. It is now widely used, however, to describe “the total of all transfer function manipulations” (i.e., including departures from a true power-law function), whether inherent or intentionally introduced to act upon the video signal for the purpose of reducing the bandwidth for signal processing, making the image on the final display conform to preconceived artistic objectives, or providing noise suppression, or even bit-rate reduction.