Contour detection

Hello,

I would like to ask if OpenCV is the right tool and fast enough to do the following as shown in the image:

What is happening here:

  1. I want to “fake” expensive boolean-union operation of 2D polygons (few hundred of them) by using OpenCV. Or at least get points on the boundary.
  2. I need to have a relatively good resolution.
  3. I will need to run this operation a few hundreds of times.

What method would you suggest? Is it FindContours or other documented method?
Maybe you could explain how fast such algorithm could run.

Thank you in advance.