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Program: Visualization Toolkit
Module: vtkPCAAnalysisFilter.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or for details.
This software is distributed WITHOUT ANY WARRANTY; without even
PURPOSE. See the above copyright notice for more information.
// .NAME vtkPCAAnalysisFilter - Performs principal component analysis of a set of aligned pointsets
// .SECTION Description
// 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:
// .SECTION Caveats
// All of the input pointsets must have the same number of points.
// .SECTION Thanks
// Rasmus Paulsen and Tim Hutton who developed and contributed this class
// .SECTION See Also
// vtkProcrustesAlignmentFilter
#ifndef __vtkPCAAnalysisFilter_h
#define __vtkPCAAnalysisFilter_h
#include "vtkPointSetAlgorithm.h"
class vtkFloatArray;
class vtkPointSet;
class VTK_HYBRID_EXPORT vtkPCAAnalysisFilter : public vtkPointSetAlgorithm
// Description:
// Prints information about the state of the filter.
void PrintSelf(ostream& os, vtkIndent indent);
// Description:
// Creates with similarity transform.
static vtkPCAAnalysisFilter *New();
// Description:
// Get the vector of eigenvalues sorted in descending order
vtkGetObjectMacro(Evals, vtkFloatArray);
// Description:
// Specify how many pointsets are going to be given as input.
void SetNumberOfInputs(int n);
// Description:
// Specify the input pointset with index idx.
// Call SetNumberOfInputs before calling this function.
void SetInput(int idx, vtkPointSet* p);
void SetInput(int idx, vtkDataObject* input);
// Description:
// Retrieve the input with index idx (usually only used for pipeline
// tracing).
vtkPointSet* GetInput(int idx);
// Description:
// 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 GetParameterisedShape(vtkFloatArray *b, vtkPointSet* shape);
// Description:
// 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]
void GetShapeParameters(vtkPointSet *shape, vtkFloatArray *b, int bsize);
// Description:
// Retrieve how many modes are necessary to model the given proportion of the variation.
// proportion should be between 0 and 1
int GetModesRequiredFor(double proportion);
// Description:
// Usual data generation method.
virtual int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);
virtual int FillInputPortInformation(int port, vtkInformation *info);
vtkPCAAnalysisFilter(const vtkPCAAnalysisFilter&); // Not implemented.
void operator=(const vtkPCAAnalysisFilter&); // Not implemented.
// Eigenvalues
vtkFloatArray *Evals;
// Matrix where each column is an eigenvector
double **evecMat2;
// The mean shape in a vector
double *meanshape;
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