In OpenCV, different functions are aimed at finding approximations for different types of curves: cv2.fitEllipse for ellipses and cv2.fitLine for lines. Both perform similar actions, minimize distances between points from the set we're fitting to the resulting curve, and require some minimal number of points to fit (five for cv2.fitEllipse and two for cv2.fitLine).
cv2.fitEllipse only accepts the argument of a set of two-dimensional points, for which we need to find curve parameters, and it returns the found ones, center point, half axes lengths, and rotation angle. These parameters can be directly passed to the cv2.ellipse drawing function when we want to display the result.
Another function, cv2.line, has more parameters. ...
