class for representing parameterized image warps, such as homography, displacement, ... More...

#include <Image/TextureTransform.hh>

Inheritance diagram for BIAS::TextureTransform:

Collaboration diagram for BIAS::TextureTransform:

Public Member Functions
virtual TextureTransform *	Clone () const =0
	virtual covariant copy constructor, caller must eventually destroy the created object More...

virtual void	ComposeWithInverseDeltaP (const Vector< double > &deltaP)=0
	concatenate this and an inverse transform with param deltaP and save new parameter vector to this. More...

virtual Vector< double >	GetInverseParameters () const
	returns parameter vector which undoes the current warp More...

void	GetParameters (Vector< double > &p) const
	get the current parameter vector More...

virtual int	MapBackward (const HomgPoint2D &sink, HomgPoint2D &source) const =0
	map a point in image "source" to a point in image "sink" More...

virtual int	MapForward (const HomgPoint2D &src, HomgPoint2D &sink) const =0
	map a point in image "source" to a point in image "sink" More...

virtual int	ParameterInversionJacobian (Matrix< double > &Jac) const
	compute parameters for inverse operation and obtain the jacobian of the inverse parameters with respect to the original parameters for error propagation More...

virtual int	ParameterJacobianBackward (Matrix< double > &Jac, const HomgPoint2D &sink)
	transformed position change when parameters change More...

virtual int	ParameterJacobianForward (Matrix< double > &Jac, const HomgPoint2D &src)
	transformed position change when parameters change More...

virtual bool	ParameterJacobianIsConstant () const =0
	return true, if the parameter jacobian does not depend on the image position More...

virtual void	SetParameters (const Vector< double > &p)=0
	override the current state with the new parameters, the meaning of the parameters is defined in the derived class'es SetParameters(). More...

virtual int	TextureJacobianBackward (const HomgPoint2D &sink, Matrix2x2< double > &Jac) const
	shape change of the local region when mapping backward More...

virtual int	TextureJacobianForward (const HomgPoint2D &src, Matrix2x2< double > &Jac) const
	shape change of the local region when mapping forward More...

virtual bool	TextureJacobianIsConstant () const =0
	return true if the texture jacobian does not depend on the image position More...

virtual	~TextureTransform ()

Protected Attributes
Vector< double >	P_
	current set of parameters, see SetParameters for meaning More...

Detailed Description

class for representing parameterized image warps, such as homography, displacement, ...

These classes can be exploited for mapping of images ("stitching") or for registration (gradient based estimation of the warp parameters ("KLT"), see BIAS::ImageAlignment, BIAS::BackwardMapping).

This base class only defines the interface for all derived transforms. The transformations must form a group, i.e. each concatenation of transformations of the same class must also be a transformation of that class: For instance, two displacements concatenated are expressable as one "big" displacement. You must specify how to fuse the parameters into the parameter for the concatenated transform (e.g. addition).

The transformations must depend on a minimal number of parameters, e.g. 6 parameters for the affine transformation. The parameter vector 0 must represent the identity warp.

You must at least provide the MapBackward and MapForward function. You can also provide the TextureJacobian functions, which - given two neighboring pixels in one image - measure their distance in the other image (imagine "local magnification"). These functions are needed for anti-aliased BackwardMapping and they can be approximated numerically very stable and well (but due to sampling not very fast). If you are interested in gradient based image registration, you should also provide the parameter jacobians, which tell how the mapping changes, when the parameters change. The approximation of these Jacobians is heuristic and presumably not very good. See TextureTransformHomography for an example.

Author: koeser 01/2008

Examples:: ExampleAlignment.cpp.

Definition at line 73 of file TextureTransform.hh.

Constructor & Destructor Documentation

virtual BIAS::TextureTransform::~TextureTransform ( )

inlinevirtual

Definition at line 76 of file TextureTransform.hh.

Member Function Documentation

virtual TextureTransform* BIAS::TextureTransform::Clone ( ) const

pure virtual

virtual covariant copy constructor, caller must eventually destroy the created object

Implemented in BIAS::TextureTransformSimilar, BIAS::TextureTransformEuclidian, BIAS::TextureTransformRotation, BIAS::TextureTransformDisplacement, BIAS::TextureTransformAffine, BIAS::TextureTransformDisparity, and BIAS::TextureTransformHomography.

Referenced by BIAS::ImageAlignment::Align(), BIAS::TextureMapping< InputStorageType, OutputStorageType >::operator=(), BIAS::TextureMapping< InputStorageType, OutputStorageType >::SetTextureTransform(), and BIAS::ImageAlignment::SetTextureTransform().

virtual void BIAS::TextureTransform::ComposeWithInverseDeltaP ( const Vector< double > & deltaP )

pure virtual

concatenate *this and an inverse transform with param deltaP and save new parameter vector to *this.

Apart from very simple transformations like displacement THIS IS NOT A SIMPLE ADDITION but rather a multiplication-like operation!

This function is particularly important for inverse compositional image alignment (KLT)

Implemented in BIAS::TextureTransformSimilar, BIAS::TextureTransformEuclidian, BIAS::TextureTransformRotation, BIAS::TextureTransformDisplacement, BIAS::TextureTransformDisparity, BIAS::TextureTransformAffine, and BIAS::TextureTransformHomography.

Referenced by BIAS::ImageAlignment::Align().

virtual Vector<double> BIAS::TextureTransform::GetInverseParameters ( ) const

inlinevirtual

returns parameter vector which undoes the current warp

Reimplemented in BIAS::TextureTransformAffine.

Examples:: ExampleAlignment.cpp.

Definition at line 130 of file TextureTransform.hh.

Referenced by BIAS::ImageAlignment::Align().

void BIAS::TextureTransform::GetParameters ( Vector< double > & p ) const

inline

get the current parameter vector

Definition at line 83 of file TextureTransform.hh.

Referenced by BIAS::ImageAlignment::Align().

virtual int BIAS::TextureTransform::MapBackward	(	const HomgPoint2D &	sink,
		HomgPoint2D &	source
	)		const

pure virtual

map a point in image "source" to a point in image "sink"

Implemented in BIAS::TextureTransformSimilar, BIAS::TextureTransformEuclidian, BIAS::TextureTransformRotation, BIAS::TextureTransformDisplacement, BIAS::TextureTransformDisparity, BIAS::TextureTransformHomography, and BIAS::TextureTransformAffine.

Referenced by BIAS::ImageAlignment::Align().

virtual int BIAS::TextureTransform::MapForward	(	const HomgPoint2D &	src,
		HomgPoint2D &	sink
	)		const

pure virtual

map a point in image "source" to a point in image "sink"

Implemented in BIAS::TextureTransformSimilar, BIAS::TextureTransformEuclidian, BIAS::TextureTransformHomography, BIAS::TextureTransformDisplacement, BIAS::TextureTransformAffine, BIAS::TextureTransformRotation, and BIAS::TextureTransformDisparity.

Referenced by TextureJacobianForward().

virtual int BIAS::TextureTransform::ParameterInversionJacobian ( Matrix< double > & Jac ) const

inlinevirtual

compute parameters for inverse operation and obtain the jacobian of the inverse parameters with respect to the original parameters for error propagation

Reimplemented in BIAS::TextureTransformEuclidian, BIAS::TextureTransformRotation, BIAS::TextureTransformDisplacement, BIAS::TextureTransformDisparity, BIAS::TextureTransformAffine, and BIAS::TextureTransformHomography.

Definition at line 124 of file TextureTransform.hh.

Referenced by BIAS::ImageAlignment::Align().