jhpro.fit

Class FitEllipse2D

java.lang.Object

jhpro.fit.FitEllipse2D

public class FitEllipse2D
extends java.lang.Object

Fit 2D data points with a ellipse using least-square fitting. The method implements the direct algorithm of Fitzgibbon et al, improved by Halir et al, to find the ellipse which best approximates a collection of points. The ellipse is defined through the 6 coefficients of its algebraic equation:

A*x**2 + B*x*y + C*y**2 + D*x + E*y + F = 0

It can also compute the ellipse characteristics (center, theta, major, minor) from its algebraic equation.

Constructor Summary

Constructors

Constructor and Description
FitEllipse2D(double[] x, double[] y) Creates a new instance of Ellipse, defined by a set of points
FitEllipse2D(P1D p) Creates a new instance of Ellipse, defined by P1D

Method Summary

Modifier and Type	Method and Description
void	doc() Show online documentation.
double	getAngle() Report the angle between the major axis and the abscissae axis
java.awt.geom.Point2D.Double	getCenter() Report the center of the ellipse, using the same coordinate system as the defining data points
double	getCenterX() Report the center of the ellipse in X
double	getCenterY() Report the center of the ellipse in Y
double[]	getCoefficients() Report the coefficients of the ellipse, as defined by the algebraic equation
double	getDistance() Report the mean algebraic distance between the data points and the ellipse
Ellipse	getEllipse() Return fitted ellipse.
Ellipse2D	getEllipse2D() Return fitted ellipse.
java.lang.Double	getMajor() Report the 1/2 length of the major axis
java.lang.Double	getMinor() Report the 1/2 length of the minor axis
static void	main(java.lang.String[] args)

Methods inherited from class java.lang.Object

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

Constructor Detail

FitEllipse2D

public FitEllipse2D(double[] x,
                    double[] y)

Creates a new instance of Ellipse, defined by a set of points

Parameters:

x - array of abscissae

y - array of ordinates

FitEllipse2D

public FitEllipse2D(P1D p)

Creates a new instance of Ellipse, defined by P1D

Parameters:

P1D - input

Method Detail

getAngle

public double getAngle()

Report the angle between the major axis and the abscissae axis

Returns:

the major axis angle, in radians

getCenter

public java.awt.geom.Point2D.Double getCenter()

Report the center of the ellipse, using the same coordinate system as the defining data points

Returns:

the ellipse center

getCenterX

public double getCenterX()

Report the center of the ellipse in X

Returns:

the ellipse center in X

getCenterY

public double getCenterY()

Report the center of the ellipse in Y

Returns:

the ellipse center in Y

getEllipse2D

public Ellipse2D getEllipse2D()

Return fitted ellipse.

Returns:

fitted ellipse.

getEllipse

public Ellipse getEllipse()

Return fitted ellipse.

Returns:

fitted ellipse.

getCoefficients

public double[] getCoefficients()

Report the coefficients of the ellipse, as defined by the algebraic equation

Returns:

the algebraic coefficients, all packed in one array

getDistance

public double getDistance()

Report the mean algebraic distance between the data points and the ellipse

Returns:

the mean algebraic distance

getMajor

public java.lang.Double getMajor()

Report the 1/2 length of the major axis

Returns:

the half major length

getMinor

public java.lang.Double getMinor()

Report the 1/2 length of the minor axis

Returns:

the half minor length

main

public static void main(java.lang.String[] args)

doc

public void doc()

Show online documentation.