I am not quite sure I completely understand your question, but if I did correctly, and you know which region you want to emphasize, you could do something like this.
Click on the Image object and navigate to Mask tool:
Select the Freehand shape:
Mark the region of your interest:
And copy the selection as an Image object:
Then, paste and store the copied image:
Then, use RegionBinarize:
You can play with threshold, but I hope you now have the idea how to do it. Note, that this only applies to the case when you know in prior and can do the manual segmentation, otherwise, if you want to do it programmatically, you will have to figure out what is your region of interest first.
Mikayel
