georegression.fitting.ellipse

Class FitEllipseAlgebraic

java.lang.Object

georegression.fitting.ellipse.FitEllipseAlgebraic

public class FitEllipseAlgebraic
extends java.lang.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 Summary

Constructors

Constructor and Description
FitEllipseAlgebraic()

Method Summary

Modifier and Type	Method and Description
EllipseQuadratic_F64	getEllipse()
boolean	process(java.util.List<Point2D_F64> points)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FitEllipseAlgebraic

public FitEllipseAlgebraic()

Method Detail

process

public boolean process(java.util.List<Point2D_F64> points)

getEllipse

public EllipseQuadratic_F64 getEllipse()