org.openimaj.math.geometry.shape.algorithm

Class ProcrustesAnalysis

java.lang.Object

org.openimaj.math.geometry.shape.algorithm.ProcrustesAnalysis

public class ProcrustesAnalysis
extends Object

Ordinary Procrustes Analysis between two sets of corresponding PointLists. It is assumed that the number of points in the PointLists is equal, and that their is a one-to-one correspondance between the ith point in each list.

Author:

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

Field Summary

Fields

Modifier and Type	Field and Description
protected PointList	reference
protected Point2d	referenceCog
protected boolean	rotate
protected double	scaling

Constructor Summary

Constructors

Constructor and Description
ProcrustesAnalysis(PointList reference) Construct the ProcrustesAnalysis with the given reference shape.
ProcrustesAnalysis(PointList reference, boolean normalise) Construct the ProcrustesAnalysis with the given reference shape.

Method Summary

Modifier and Type	Method and Description
Jama.Matrix	align(PointList toAlign) Align the given shape to the reference.
static float	computeProcrustesDistance(PointList l1, PointList l2) Compute the Procrustes Distance between two PointLists.
protected static double	computeScale(PointList pl, double tx, double ty)

Methods inherited from class java.lang.Object

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

Field Detail

reference

protected PointList reference

referenceCog

protected Point2d referenceCog

scaling

protected double scaling

rotate

protected boolean rotate

Constructor Detail

ProcrustesAnalysis

public ProcrustesAnalysis(PointList reference)

Construct the ProcrustesAnalysis with the given reference shape.

Parameters:

reference - The reference shape.

ProcrustesAnalysis

public ProcrustesAnalysis(PointList reference,
                          boolean normalise)

Construct the ProcrustesAnalysis with the given reference shape. The reference shape is optionally normalised to a standardised scale and translated to the origin.

Parameters:

reference - The reference shape.

normalise - if true, then the reference is normalised (changing the reference shape itself).

Method Detail

computeScale

protected static double computeScale(PointList pl,
                                     double tx,
                                     double ty)

align

public Jama.Matrix align(PointList toAlign)

Align the given shape to the reference. The alignment happens inplace, so the input points are modified. The matrix used to transform the points is returned.

Parameters:

toAlign - transform matrix

Returns:

aligned points (reference to toAlign)

Throws:

IllegalArgumentException - if the input is null or has a different size to the reference.

computeProcrustesDistance

public static float computeProcrustesDistance(PointList l1,
                                              PointList l2)

Compute the Procrustes Distance between two PointLists. If the distance is 0, then the shapes overlap exactly.

Parameters:

l1 - first shape

l2 - second shape

Returns:

the calculated distance.

Throws:

IllegalArgumentException - if the input is null or has a different size to the reference.