Avision AV8300 - Manual (Page 40)

6-3
6.16 CURVES
When you select the Curves button, a dialog box appears that allows you to
adjust the midtone of the image without losing details in the lightest and
darkest areas.
Select the Curve or Line button, depending on if you want a curved or an
angled setting. Place the mouse cursor over the line, click the right mouse
button, and drag the line to set the curve you want.