Updates snake in order to minimize its total energy that is a sum of internal energy that depends on contour shape (the smoother contour is, the smaller internal energy is) and external energy that depends on the energy field and reaches minimum at the local energy extremums that correspond to the image edges in case of image gradient.

C# | Visual Basic | Visual C++ |
public void Snake( Point[] contour, float alpha, float beta, float gamma, Size windowSize, MCvTermCriteria tc, bool calculateGradiant )

- contour (array< Point >[]()[])
- Some existing contour. It's value will be update by this function
- alpha (Single)
- Weight[s] of continuity energy, single float or array of length floats, one per each contour point
- beta (Single)
- Weight[s] of curvature energy, similar to alpha.
- gamma (Single)
- Weight[s] of image energy, similar to alpha.
- windowSize (Size)
- Size of neighborhood of every point used to search the minimum, both win.width and win.height must be odd
- tc (MCvTermCriteria)
- Termination criteria. The parameter criteria.epsilon is used to define the minimal number of points that must be moved during any iteration to keep the iteration process running. If at some iteration the number of moved points is less than criteria.epsilon or the function performed criteria.max_iter iterations, the function terminates.
- calculateGradiant (Boolean)
- If true, the function calculates gradient magnitude for every image pixel and considers it as the energy field, otherwise the input image itself is considered