Gamma correction | Dynamic gamma correction
NonlinearoperationTheeffectofgammacorrectiononanimage:Theoriginalimagewastakentovaryingpowers,showingthatpowerslargerthan1maketheshadowsdarker,whilepowerssmallerthan1makedarkregionslighter.Gammacorrectionorgammaisanonlinearoperationusedtoencodeanddecodeluminanceortristimulusvaluesinvideoorstillimagesystems.[1]Gammacorrectionis,inthesimplestcases,definedbythefollowingpower-lawexpression:Vout=AVinγ,{displaystyleV_{ext{out}}=AV_{ext{in}}{gamma},}wherethenon-negativerealinputvalueVin{displaystyl...
Nonlinear operation
The effect of gamma correction on an image: The original image was taken to varying powers, showing that powers larger than 1 make the shadows darker, while powers smaller than 1 make dark regions lighter.Gamma correction or gamma is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems.[1] Gamma correction is, in the simplest cases, defined by the following power-law expression:
Vout=AVinγ,{displaystyle V_{ ext{out}}=AV_{ ext{in}}{gamma },}where the non-negative real input value Vin{displaystyle V_{ ext{in}}} is raised to the power γ{displaystyle gamma } and multiplied by the constant A to get the output value Vout{displaystyle V_{ ext{out}}}. In the common case of A = 1, inputs and outputs are typically in the range 0–1.
A gamma value γ<1{displaystyle gamma <1} is sometimes called an encoding gamma, and the process of encoding with this compressive power-law non...