Gamma correction means to make Gamma correction. That is, gamma correction is used to alter the output levels of a monitor.
Gamma refers to the brightness that is displayed on your monitor or computer display. This is a type of setting that determines how bright your display’s output is going to be.
By the way gamma setting is definitely affected by the brightness of a display, but it is not completely identical to the brightness.
The reason for this is that gamma adjustments are not linear, as are brightness levels. The gamma setting applies a function to input levels, which produces the final output level.
You can visualize this function as a curved line rather than a straight line. It also means that extreme dark and light points are not affected much like midtones, which are enhanced more because they are non-linear function. The gamma setting affects both brightness and contrast of a display.
One of the main reasons why gamma correction is used is that the input signal, or voltage, that is sent to a monitor is not that much to produce a bright image.
So if the gamma is not altered, then the images will darken on your screen and it will become very difficult to see them. Similarly, if gamma correction is applied, then the brightness and contrast of the display are increased, which make the images brighter and also show more natural looking.