Exclude part of image target

Hi!

Context:

I wanted to make an image as a target, in which the user might doodle in a small area in the middle. 

So the question is that is there any possibility of not processing the middle part as part of the image recognizing process? 

I have read that it wasnt possible in a post in 2015.

Is there any update after 2015 or any work around to make this possible?

Thanks!