Gamma correction is a kind of pre-distortion correction applied on images or video frames to offset the non-linear behavior of display systems. CRT (Cathode Ray Tube) displays exhibit inherent non-linearity in mapping voltage to light intensity. The intensity of the displays is proportional to some power, referred to as gamma, of the signal amplitude. Gamma is usually greater than one and hence the displays have lower gain at low intensities and progressively larger gain at higher intensities. Gamma correction involves multiplying the input signal with the inverse of the display transfer function to achieve a linear intensity response for the display with respect to the original input signal.
The non-CRT displays such as Plasma, LCOS (Liquid Crystal on Silicon), and DLP (Digital Light Processing) have different transfer characteristics. Several gamma correction methods and values are used in television and display systems. Sometimes, the display itself can have linear characteristics, but a gamma transformation (usually called degamma) may be required because of an earlier gamma correction made to the incoming signal.
The Lattice Gamma Corrector IP core is a widely parameterizable and multi-color plane gamma correction system. It can support almost any custom gamma correction requirement.