This is a function of image binarization. Otsu thresholding is a simple and effective global automatic thresholding method for binarizing grayscale images such as objects and backgrounds.
I made and ran it on python27 @2.7.12_1, opencv @3.1.0_1+java+python27+qt4+vtk and py27-numpy @1.11.1_0+gfortran.
git clone to your computer from here.
To run it;
python Binarization_otsu.py
Input Image Filename : [image filename path]
Output Image Filename : [image filename path]
tokkuman