Numpy adaptation of the Chan-Vese level-sets code from creaseg (http:https://www.creatis.insa-lyon.fr/~bernard/creaseg/). The relevant file from the original source code is in the creaseg/ folder.
The code from Burak Bayramli (http:https://ascratchpad.blogspot.com/2011/03/image-segmentation-using-active.html) has been useful when performing this adaptation.

The Chan-Vese level sets model aims at minimizing the energy:

where I is the image, C is the boundary of the segmented region, c_1 and c_2 are the averages of I respectively inside and outside C, and kappa is the curvature of C.

python chanvese.py

T. Chan and L. Vese. "Active contours without edges". IEEE Transactions on Image Processing. Volume 10, pp. 266-277, February 2001.