Package georegression.fitting.curves

Class FitEllipseWeightedAlgebraic_F64

java.lang.Object
georegression.fitting.curves.FitEllipseWeightedAlgebraic_F64
public class FitEllipseWeightedAlgebraic_F64 extends Object

Fits an ellipse to a set of points in "closed form" by minimizing algebraic least-squares error. The method used is described in [1] and is a repartitioning of the solution describe in [2], with the aim of improving numerical stability. The found ellipse is described using 6 coefficients, as is shown below. F(x,y) = a*x^2 + 2*b*x*y + c*y^2 + 2*d*x + 2*e*y + f = 0 and b^2 - 4*ac < 0

One peculiarity of this algorithm is that it's less stable when perfect data is provided. This instability became evident when constructing unit tests and some of them failed. Tests on the original Matlab code also failed.

  • [1] Radim Halir and Jan Flusser, "Numerically Stable Direct Least Squares Fitting Of Ellipses" 1998
  • [2] Fitzgibbon, A. W., Pilu, M and Fischer, R. B.: "Direct least squares fitting of ellipses" Technical Report DAIRP-794, Department of Artificial Intelligence, The University of Edinburgh, January 1996

  • Constructor Details

    • FitEllipseWeightedAlgebraic_F64

      public FitEllipseWeightedAlgebraic_F64()

  • Method Details

    • process

      public boolean process(List<Point2D_F64> points, double[] weights)
      Fits the ellipse to the line
      Parameters:
      points - Set of points that are to be fit
      weights - Weight or importance of each point. Each weight must be a positive number
      Returns:
      true if successful or false if it failed

    • getEllipse

      public EllipseQuadratic_F64 getEllipse()