Fits an ellipse around a set of 2D points

rct = cv.fitEllipse(points)

Input

• points Input 2D point set, stored in numeric array (Nx2/Nx1x2/1xNx2) or cell array of 2-element vectors ({[x,y], ...}).

Output

• rct Output rotated rectangle struct with the following fields:
  • center The rectangle mass center [x,y].
  • size Width and height of the rectangle [w,h].
  • angle The rotation angle in a clockwise direction. When the angle is 0, 90, 180, 270 etc., the rectangle becomes an up-right rectangle.

The function calculates the ellipse that fits (in a least-squares sense) a set of 2D points best of all. It returns the rotated rectangle in which the ellipse is inscribed. The first algorithm described by [Fitzgibbon95] is used. Developer should keep in mind that it is possible that the returned ellipse/rotatedRect data contains negative indices, due to the data points being close to the border of the containing Mat element.

References

[Fitzgibbon95]:

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.