Adjusting Brightness, Contrast, and Gamma

The brightness, contrast, and gamma controls provide three ways to adjust pixel intensities in order to enhance objects of interest in the image.  They allow you to increase the intensity values along some parts of the range of intensities, and decrease intensity values along other parts of the range. 

Note: The brightness, contrast, and gamma controls make LUT adjustments to the intensities within the current display range -- that is, the intensities between the defined black level and white level.  Click here to learn more about defining a display range.

To adjust brightness, contrast, or gamma:

Find the Display group on the Adjust tab’s ribbon.

As you move the sliders, the image in the workspace displays the changes in intensity.

Use the sliders to adjust the image.

Brightness:  Increases/decreases all intensity values uniformly.  In the example below, brightness has been increased from the original.

Contrast:  Increases/decreases high and low intensity values reciprocally (that is, as the high values are increased, the corresponding low values are decreased, and vice versa).  In the example below, contrast has been increased from the original.

Gamma:  Adjusts the contrast for the high and low intensity ranges simultaneously.  In the example below, gamma has been decreased from the original.