The function cv::fitEllipse gives three algorithms for fitting ellipse by least square method. In the source code, there is a note that “New fitellipse algorithm, contributed by Dr. Daniel Weiss”. Who is Dr. Daniel Weiss? Where can I find any papers or details about his work on fitting ellipse algorithm?

I have read the paper given by OpenCV: Structural Analysis and Shape Descriptors.

However, I am still confused.

I just want to know

- Why does the algorithm need re-fit? It first fits for parameter A-E, and then re-fit for parameters A-C with those center coordinates.
- Ellipse need the satisfy the constraint of 4ab-c^2 > 0, how does the algorithm satisfy it?