Visualize DOF in game

Hello mate, as the title suggest, i want to visualize Depth of Field layer in game, just like the one in the editor:

https://docs.unrealengine.com/latest/images/Engine/Rendering/PostProcessEffects/DepthOfField/dof_layers_visualize.jpg

Or something simpler will do. Any document or tip will be much help to me. Thank you all very much.

Hi!

You can experiment with posprocess material and Depth Fade node

This is what i come up with, following your bluprint:

Thank you very much.

Sorry to bother you again, but how can i change the width of the middle region (aka the focal region)? Thank you very much.