vtkPCAAnalysisFilter Class Reference

#include <vtkPCAAnalysisFilter.h>

Inheritance diagram for vtkPCAAnalysisFilter:

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Collaboration diagram for vtkPCAAnalysisFilter:

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List of all members.

Detailed Description

Performs principal component analysis of a set of aligned pointsets.

vtkPCAAnalysisFilter is a filter that takes as input a set of aligned pointsets (any object derived from vtkPointSet) and performs a principal component analysis of the coordinates. This can be used to visualise the major or minor modes of variation seen in a set of similar biological objects with corresponding landmarks. vtkPCAAnalysisFilter is designed to work with the output from the vtkProcrustesAnalysisFilter

Call SetNumberOfInputs(n) before calling SetInput(0) ... SetInput(n-1). Retrieve the outputs using GetOutput(0) ... GetOutput(n-1).

vtkPCAAnalysisFilter is an implementation of (for example):

T. Cootes et al. : Active Shape Models - their training and application. Computer Vision and Image Understanding, 61(1):38-59, 1995.

The material can also be found in Tim Cootes' ever-changing online report published at his website: http://www.isbe.man.ac.uk/~bim/

Warning:: All of the input pointsets must have the same number of points.

Thanks:: Rasmus Paulsen and Tim Hutton who developed and contributed this class

See also:: vtkProcrustesAlignmentFilter

Tests:: vtkPCAAnalysisFilter (Tests)

Definition at line 61 of file vtkPCAAnalysisFilter.h.


Public Types
typedef vtkPointSetAlgorithm	Superclass
Public Member Functions
virtual const char *	GetClassName ()
virtual int	IsA (const char *type)
void	PrintSelf (ostream &os, vtkIndent indent)
void	SetNumberOfInputs (int n)
vtkPointSet *	GetInput (int idx)
void	GetParameterisedShape (vtkFloatArray b, vtkPointSet shape)
void	GetShapeParameters (vtkPointSet shape, vtkFloatArray b, int bsize)
int	GetModesRequiredFor (double proportion)

virtual vtkFloatArray *	GetEvals ()

void	SetInput (int idx, vtkPointSet *p)
void	SetInput (int idx, vtkDataObject *input)
Static Public Member Functions
static int	IsTypeOf (const char *type)
static vtkPCAAnalysisFilter *	SafeDownCast (vtkObject *o)
static vtkPCAAnalysisFilter *	New ()
Protected Member Functions
	vtkPCAAnalysisFilter ()
	~vtkPCAAnalysisFilter ()

virtual int	RequestData (vtkInformation , vtkInformationVector , vtkInformationVector )
virtual int	FillInputPortInformation (int port, vtkInformation *info)

Member Typedef Documentation

typedef vtkPointSetAlgorithm vtkPCAAnalysisFilter::Superclass

Reimplemented from vtkPointSetAlgorithm.

Definition at line 64 of file vtkPCAAnalysisFilter.h.

Constructor & Destructor Documentation

vtkPCAAnalysisFilter::vtkPCAAnalysisFilter ( ) [protected]

vtkPCAAnalysisFilter::~vtkPCAAnalysisFilter ( ) [protected]

Member Function Documentation

virtual const char* vtkPCAAnalysisFilter::GetClassName ( ) [virtual]

Reimplemented from vtkPointSetAlgorithm.

static int vtkPCAAnalysisFilter::IsTypeOf ( const char * name ) [static]

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkPointSetAlgorithm.

virtual int vtkPCAAnalysisFilter::IsA ( const char * name ) [virtual]

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkPointSetAlgorithm.

static vtkPCAAnalysisFilter* vtkPCAAnalysisFilter::SafeDownCast ( vtkObject * o ) [static]

Reimplemented from vtkPointSetAlgorithm.

void vtkPCAAnalysisFilter::PrintSelf	(	ostream &	os,
		vtkIndent	indent
	)			`[virtual]`

Prints information about the state of the filter.

Reimplemented from vtkPointSetAlgorithm.

static vtkPCAAnalysisFilter* vtkPCAAnalysisFilter::New ( ) [static]

Creates with similarity transform.

Reimplemented from vtkPointSetAlgorithm.

virtual vtkFloatArray* vtkPCAAnalysisFilter::GetEvals ( ) [virtual]

Get the vector of eigenvalues sorted in descending order

void vtkPCAAnalysisFilter::SetNumberOfInputs ( int n )

Specify how many pointsets are going to be given as input.

void vtkPCAAnalysisFilter::SetInput	(	int	idx,
		vtkPointSet *	p
	)

Specify the input pointset with index idx. Call SetNumberOfInputs before calling this function.

Reimplemented from vtkPointSetAlgorithm.

void vtkPCAAnalysisFilter::SetInput	(	int	idx,
		vtkDataObject *	input
	)

Specify the input pointset with index idx. Call SetNumberOfInputs before calling this function.

Reimplemented from vtkPointSetAlgorithm.

vtkPointSet* vtkPCAAnalysisFilter::GetInput ( int idx )

Retrieve the input with index idx (usually only used for pipeline tracing).

void vtkPCAAnalysisFilter::GetParameterisedShape	(	vtkFloatArray *	b,
		vtkPointSet *	shape
	)

Fills the shape with: mean + b[0] * sqrt(eigenvalue[0]) * eigenvector[0] + b[1] * sqrt(eigenvalue[1]) * eigenvector[1] ... + b[sizeb-1] * sqrt(eigenvalue[bsize-1]) * eigenvector[bsize-1] here b are the parameters expressed in standard deviations bsize is the number of parameters in the b vector This function assumes that shape is allready allocated with the right size, it just moves the points.

void vtkPCAAnalysisFilter::GetShapeParameters	(	vtkPointSet *	shape,
		vtkFloatArray *	b,
		int	bsize
	)

Return the bsize parameters b that best model the given shape (in standard deviations). That is that the given shape will be approximated by: shape ~ mean + b[0] * sqrt(eigenvalue[0]) * eigenvector[0] + b[1] * sqrt(eigenvalue[1]) * eigenvector[1] ... + b[bsize-1] * sqrt(eigenvalue[bsize-1]) * eigenvector[bsize-1]

int vtkPCAAnalysisFilter::GetModesRequiredFor ( double proportion )

Retrieve how many modes are necessary to model the given proportion of the variation. proportion should be between 0 and 1