This is a fast non-iterative ellipse fit, and among fast non-iterative ellipse fits this is the most accurate and robust. It takes the xy-coordinates of data points, and returns the coefficients of the equation of the ellipse: ax^2 + bxy +

RANSAC - Robustly fits a model to data with the RANSAC algorithm-RANSAC- Robustly fits a model to data with the RANSAC algorithm

RANSACFITHOMOGRAPHY - fits 2D homography using RANSAC-RANSACFITHOMOGRAPHY- fits 2D homography using RANSAC

The polygon fits very well to the notion of cycle, and use like a closed chain lis of segments.