Kdenlive/Manual/Effects/Enhancement/Sharpen

Sharpen

The sharpen tool is a port of unsharp mask from Mplayer. The parameters are the usual ones for unsharp masking, The "size" means the size of the blur, and the amount is how much of the blurred version gets subtracted.

See this tutorial that describes how to use

Alpha Manipulation>Blue Screen
rotoscoping
Composite Transition
Crop and Transform>Pan and Zoom effect
Sharpen Effect
Alpha Manipulation>Alpha Operations