Object correct labeling when it is within another object

I have an overlayed image, the first image contains the red boxes that I have labelled (here: 1 and 2) already. The second image contains the blue boxes but has different labels (here: 3 and 4). However, I would like to relabel these objects in a way, that whenever the blue box is completely inside the area of the red box they will share the same label.

I attached a short illustration to make it clear and hope you can help me with this problem.

Answer 1

[Prashant Arora]

You can use the function "inpolygon" to check if one polygon lies inside the other.

http://www.mathworks.com/help/matlab/ref/inpolygon.html?searchHighlight=inpolygon

To extract polygons/squares from the images, you can use "regionprops" function.

http://www.mathworks.com/help/images/ref/regionprops.html