Masking Camera Image / Removing Blur Offset

Hi everyone,

I am currently developing a 2D UI with Unity. I have two cameras that see two different canvases (implemented via culling mask) so that I can blur the “bottom” camera image and lay the “top” camera’s on top of the first one. This is working fine so far.

My issue is the following:
There is a scroll rect in the “bottom” camera layer that uses a mask so that everything stays within the white border - see first attached screenshot.

However, when I blur the cameras image via the Blur (Optimized) component, the blur leads to the white part on the right hand side extending over the border of the mask (which makes sense since the whole camera image is being blurred) - see second attached screenshot

My question is: can I somehow mask the “bottom” camera’s image so that the blurred image doesn’t extend beyond the border of the unblurred version?

Thanks in advance!

I solved the problem by creating a png that has a transparent rectangle in the center and put it on the canvas that is being seen by the “top” camera. This basically overlays the extension caused by the blur.