BackgroundSubtractorCNT is in opencv 3.3.0. It is part of the opencv_contrib project.
OpenCV GUI CanvasCV makes line crossing easy with the LineCrossing shape.
CanvasCV is an OpenCV GUI framework for simple user ineraction. It works inside the OpenCV native windows. It provides interactive shapes and widgets in a non intrusive design.
Some cookbook receipts on getting started with TBB and OpenCV.
Learn how to use BackgroundSubtractorCNT from python.
Build a faster OpenCV 3.1.0 for Raspberry Pi3
Learn and download a faster background subtraction implementation