org.openimaj.math.geometry.shape

Class EllipseUtilities

java.lang.Object

org.openimaj.math.geometry.shape.EllipseUtilities

public class EllipseUtilities
extends Object

An elliptical shape

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Constructor Summary

Constructors

Constructor and Description
EllipseUtilities()

Method Summary

Modifier and Type	Method and Description
static Ellipse	ellipseFromCovariance(float x, float y, Jama.Matrix sm, float sf) Construct ellipse from covariance matrix, scale-factor and centroid.
static Ellipse	ellipseFromEquation(double centerX, double centerY, double major, double minor, double rotation) Construct an ellipse using a parametric ellipse equation, namely: X(t) = centerX + major * cos(t) * cos(rotation) - minor * sin(t) * sin(rotation) Y(t) = centerY + major * cos(t) * cos(rotation) + minor * sin(t) * sin(rotation)
static Ellipse	ellipseFromGaussian(MultivariateGaussian gaussian, float scale) Construct an ellipse that encompasses the shape of a CachingMultivariateGaussian.
static Ellipse	ellipseFromSecondMoments(float x, float y, Jama.Matrix secondMoments) Construct ellipse from second moment matrix and centroid.
static Ellipse	ellipseFromSecondMoments(float x, float y, Jama.Matrix secondMoments, double scaleFactor) Construct ellipse from second moment matrix, scale-factor and centroid.
static Jama.Matrix	ellipseToCovariance(Ellipse e) Create the covariance matrix of an ellipse.
static Ellipse	fromTransformMatrix2x2(Jama.Matrix U, float x, float y, float scale) Create an ellipse.

Methods inherited from class java.lang.Object

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

Constructor Detail

EllipseUtilities

public EllipseUtilities()

Method Detail

ellipseFromEquation

public static Ellipse ellipseFromEquation(double centerX,
                                          double centerY,
                                          double major,
                                          double minor,
                                          double rotation)

Construct an ellipse using a parametric ellipse equation, namely: X(t) = centerX + major * cos(t) * cos(rotation) - minor * sin(t) * sin(rotation) Y(t) = centerY + major * cos(t) * cos(rotation) + minor * sin(t) * sin(rotation)

Parameters:

centerX -

centerY -

major -

minor -

rotation -

Returns:

an ellipse

ellipseFromSecondMoments

public static Ellipse ellipseFromSecondMoments(float x,
                                               float y,
                                               Jama.Matrix secondMoments)

Construct ellipse from second moment matrix and centroid.

Parameters:

x - x-ordinate of centroid

y - y-ordinate of centroid

secondMoments - second moments matrix

Returns:

an ellipse

ellipseFromSecondMoments

public static Ellipse ellipseFromSecondMoments(float x,
                                               float y,
                                               Jama.Matrix secondMoments,
                                               double scaleFactor)

Construct ellipse from second moment matrix, scale-factor and centroid.

Parameters:

x - x-ordinate of centroid

y - y-ordinate of centroid

secondMoments - second moments matrix

scaleFactor - the scale factor

Returns:

an ellipse

ellipseFromCovariance

public static Ellipse ellipseFromCovariance(float x,
                                            float y,
                                            Jama.Matrix sm,
                                            float sf)

Construct ellipse from covariance matrix, scale-factor and centroid.

Parameters:

x - x-ordinate of centroid

y - y-ordinate of centroid

sm - covariance matrix

sf - scale-factor

Returns:

an ellipse

ellipseToCovariance

public static Jama.Matrix ellipseToCovariance(Ellipse e)

Create the covariance matrix of an ellipse.

Parameters:

e - the ellipse

Returns:

the corresponding covariance matrix

fromTransformMatrix2x2

public static Ellipse fromTransformMatrix2x2(Jama.Matrix U,
                                             float x,
                                             float y,
                                             float scale)

Create an ellipse.

Parameters:

U -

x -

y -

scale -

Returns:

an ellipse

ellipseFromGaussian

public static Ellipse ellipseFromGaussian(MultivariateGaussian gaussian,
                                          float scale)

Construct an ellipse that encompasses the shape of a CachingMultivariateGaussian.

Parameters:

gaussian - the CachingMultivariateGaussian

scale - the relative size of the ellipse

Returns:

the ellipse