OCR Application [on hold]

I’m trying to build an OCR using Google Vision. Right now I’ve built it partially and what it does is it scans and recognize everything that it finds on the screen.

I only want a certain portion of the screen to be scanned like a rectangular portion on the screen instead of the whole screen.

Actual Screen

What I want

In the second Image, I want only the non-blurred area to act as an OCR.

How can I achieve this?