Gamma correction
Gamma correction or gamma is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following power-law expression: where the non-negative real input value is raised to the power and multiplied by the constant A to get the output value . In the common case of A = 1, inputs and outputs are typically in the range 0–1. A gamma value is sometimes called an encoding gamma, and the process of encoding with this compressive power-law nonlinearity is called gamma compression; conversely a gamma value is called a decoding gamma, and the application of the expansive power-law nonlinearity is called gamma expansion. (Wikipedia).
