1. ITK Deformable Registration
Demons
Methods

2. Deformable Registration

3. Deformable Transforms

4. Deformable Transformationy y
Transform x x
Fixed Image
Moving Image

5. Deformable Transformationy y
Transform x x
Fixed Image
Moving Image

6. Deformable Transformationy y
Transform x x
Fixed Image
Moving Image

7. Image Resampling Interpolator Fixed Image Resample Image Moving Image
Filter
Moving Image
Deformed Image
Transform

8. Image Resampling Fixed Image Interpolator Resample Image Filter
Moving Image
Orthogonal
Basis
Explicit Vector
Field
Splines
High Order
Polynomials
Deformed Image
Transform

9. Kernel Splines Transforms
Target
Landmarks
Source
Landmarks
Interpolated
Values
Displacement
Vectors

10. Kernel Spline Transforms
Thin Plates
Thin Plates R2 log R
Elastic Body
Elastic Body Reciprocal
Volume

11. Kernel Spline Transforms
InsightApplications / ThinPlateSplines

12. Resampling: Kernel Spline Transform
#include "itkImage.h"
#include "itkResampleImageFilter.h"
#include "itkLinearInterpolateImageFunction.h"
#include "itkElasticBodySplineKernelTransform.h"
typedef itk::Image< char, 2 > ImageType;
ImageType::ConstPointer fixedImage = GetFixedImage();
ImageType::ConstPointer movingImage = GetMovingImage();
typedef itk::LinearInterpolateImageFunction< ImageType, double > InterpolatorType;
InterpolatorType::Pointer interpolator = InterpolatorType::New();
typedef itk::ResampleImageFilter< ImageType,
ImageType > FilterType;
FilterType::Pointer resampler = FilterType::New();

13. Resampling: Kernel Spline Transform
typedef itk::ElasticBodySplineKernelTransform< double, 2 > TransformType;
TransformType::Pointer transform = TransformType::New();
resampler->SetInterpolator( interpolator );
resampler->SetInput( movingImage );
ImageType::RegionType region = fixedImage->GetBufferedRegion();
resampler->SetSize( region->GetSize() );
resampler->SetOutputStartIndex( region->GetIndex() );
resampler->SetOutputSpacing( fixedImage->GetSpacing() );
resampler->SetOutputOrigin( fixedImage->GetOrigin() );

14. Resampling: Kernel Spline Transform
resampler->SetTransform( transform );
typedef TransformType::PointSetType PointSetType;
PointSetType::Pointer sourceLandmarks = PointSetType::New();
PointSetType::Pointer targetLandmarks = PointSetType::New();
transform->SetSourceLandmarks( sourceLandmarks );
transform->SetTargetLandmarks( targetLandmarks );
typedef PointSetType::PointsContainer PointsContainer;
PointsContainer::Pointer sources = sourceLandmarks->GetPoints();
PointsContainer::Pointer targets = targetLandmarks->GetPoints();

15. Resampling: Kernel Spline Transform
sources->Reserve( numberOfLandmarks );
targets->Reserve( numberOfLandmarks );
typedef PointSetType::PointType PointType;
PointType source;
PointType target;
for( int i = 0; i < numberOfLandmarks; i++ ) {
inputFile >> source;
inputFile >> target;
sources->InsertElement( i, source );
targets->InsertElement( i, target ); }
transform->ComputeWMatrix();
resampler->Update(); // Finally !!
ImageType::ConstPointer deformedImage = resampler->GetOutput();

16. Kernel Spline Transforms
VolView : ITK Plugin

17. Kernel Spline Transforms
VolView : ITK Plugin

18. Deformable Transforms
Deformation Fields

19. Deformation Vector Field
ParaView:

20. Warp Image Filter #include "itkImage.h"
#include "itkWarpImageFilter.h"
#include "itkLinearInterpolateImageFunction.h"
typedef itk::Image< char, 2 > ImageType;
ImageType::ConstPointer fixedImage = GetFixedImage();
ImageType::ConstPointer movingImage = GetMovingImage();
typedef itk::LinearInterpolateImageFunction< ImageType, double > InterpolatorType;
InterpolatorType::Pointer interpolator = InterpolatorType::New();
typedef itk::Vector< float, 2 > VectorType;
typedef itk::Image< VectorType , 2 > VectorFieldType;
VectorFieldType::Pointer vectorField = GetVectorField();

21. Warp Image Filter typedef itk::WarpImageFilter< ImageType,
VectorFieldType > WarpFilterType;
WarpFilterType::Pointer warpFilter = WarpFilterType::New();
warpFilter->SetInterpolator( interpolator );
warpFilter->SetInput( movingImage );
warpFilter->SetOutputSpacing( fixedImage->GetSpacing() );
warpFilter->SetOutputOrigin( fixedImage->GetOrigin() );
warpFilter->SetDeformationField( vectorField );
warpFilter->Update();
ImageType::ConstPointer deformedImage = warpFilter->GetOutput();

22. Demons Registration
Demons Registration

23. Demons is a Family of Algorithms
Demons Registration
Demons is a Family of Algorithms

24. Demons Registration
Demons Type 0

25. Demons Registration: Type 0
Transform
Scene
Model

26. Demons Registration: Type 0
Transform
Scene
Gradients
Model

27. Demons Registration: Type 0
Transform
Scene
Forces
Model

28. Demons Registration
Demons Type 1

29. Demons Registration: Type 1
Transform
Scene
Vector Field
Model

30. Demons Registration: Type 1
Transform
Scene
Vector Field
Model

31. Demons Registration: Type 1
Transform
Scene
Vector Field
Model

32. Demons Registration: Type 1
Transform
Scene
Vector Field
Model

33. Demons Registration: Type 1
Gradient
Scene

34. Demons Registration: Type 1
Current
Estimation
Intensity
Space
Gradient
Desired
Displacement
Scene

35. Demons Registration: Type 1
Transform
Scene
Vector Field
Model

36. Demons Registration: Type 1
Scene

37. Demons Registration: Type 1
Iterations
Incremental Field
Next Field
Previous Field
Gaussian
Smoothing

38. Demons Registration: Type 1
( s – m ) . Grad(s)
V =
Grad(s)2
( s – m ) . Grad(s)
V =
Grad(s)2 + (s-m)2 K

39. Image Registration Framework
Fixed Image
Increment
Computation
PDE Solver
Moving Image
Interpolator
Deformation Field
Transform

40. Demons Registration: Type 1
#include "itkImage.h"
#include "itkDemonsRegistrationFilter.h"
typedef itk::Image< char, 2 > ImageType;
ImageType::ConstPointer fixedImage = GetFixedImage();
ImageType::ConstPointer movingImage = GetMovingImage();
typedef itk::Vector< float, 2 > VectorType;
typedef itk::Image< VectorType , 2 > VectorFieldType;
typedef itk::DemonsRegistrationFilter<
ImageType,
VectorFieldType > DemonsType;
DemonsType::Pointer demons = DemonsType::New();

41. Demons Registration: Type 1
demons->SetFixedImage( fixedImage );
demons->SetMovingImage( movingImage );
demons->SetNumberOfIterations( 200 );
demons->SetStandardDeviations( 1.0 );
demons->Update();
ImageType::ConstPointer vectorField = demons->GetOutput();

42. Demons Registration: Type 1
Scene

43. Demons Registration: Type 1
Model

44. Demons Registration: Type 1
After
Registration

45. Demons Registration: Type 1
Scene

46. Demons Registration: Type 1
Scene

47. Fixed and Moving images should have the same intensity distribution !
Requirements
Fixed and Moving images should have the same intensity distribution !

48. Eventual Preprocessing
- Histogram Matching Filter - Anisotropic Diffusion Filtering

49. Image Registration Framework
Fixed Image
Increment
Computation
PDE Solver
Moving Image
Interpolator
Deformation Field
Transform
Resampler
Moving Registered

50. Enjoy ITK !