Algorithm of ellipse fitting in OpenCV

Question

I read the code of ellipse fitting in OpenCV, the following link gives the source code of ellipse fitting in OpenCV: http://lpaste.net/161378.

I want to know some details about ellipse fitting in OpenCV, but I can not find any documents of the algorithm. In the comments, it said " New fitellipse algorithm, contributed by Dr. Daniel Weiss". But I can not find any paper about ellipse fitting of Dr. Daniel Weiss.

I have some questions of the algorithm:

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

Answer 1

我自己也在想这个问题，因为我发现算法被窃听了。请参阅此错误报告：https://github.com/Itseez/opencv/issues/6544

我试图找到Daniel Weiss博士的任何相关论文并且失败了。

Answer 2

OpenCV函数cv::fitEllipse的文档提到了这篇论文：

Andrew W Fitzgibbon and Robert B Fisher. A buyer's guide to conic fitting. In Proceedings of the 6th British conference on Machine vision (Vol. 2), pages 513–522. BMVA Press, 1995.

还有相关链接：OpenCV Ellipse fitting: extract parameters。

Answer 3

您可能会发现此回购很有用（通过点子设置）：

https://github.com/bdhammel/least-squares-ellipse-fitting

这是从Halir在此处撰写的Fitzgibbon算法升级（作为起点）的工作原理：

https://github.com/bdhammel/least-squares-ellipse-fitting/blob/master/media/WSCG98.pdf

此后，我对此进行了一些测试，似乎非常有效。请注意，回购主页面上的“示例”已过时，请查看代码本身中的example.py模块以了解其在模块导入等方面的用法。