1. https://www.sciencedirect.com/science/article/abs/pii/S0167865505003521 (Zoran Zivkovic. Efficient adaptive density estimation per image pixel for the task of background subtraction // 2005.
2. https://docs.opencv.org/4.x/d7/d4d/tutorial_py_thresholding.html
3. https://docs.opencv.org/4.x/d9/d61/tutorial_py_morphological_ops.html
4. https://docs.opencv.org/4.x/d9/d8b/tutorial_py_contours_hierarchy.html
5. https://www.visual-paradigm.com/guide/uml-unified-modeling-language/what-is-activity-diagram/