Use finite differences to estimate gradient. More...

#include <vtkFiniteDifferenceGradientEstimator.h>

Inheritance diagram for vtkFiniteDifferenceGradientEstimator:

Collaboration diagram for vtkFiniteDifferenceGradientEstimator:

Public Types
typedef vtkEncodedGradientEstimator	Superclass
Public Types inherited from vtkEncodedGradientEstimator
Public Types inherited from vtkObject

Public Member Functions
virtual const char *	GetClassName ()
virtual int	IsA (const char *type)
void	PrintSelf (ostream &os, vtkIndent indent)

virtual void	SetSampleSpacingInVoxels (int)
virtual int	GetSampleSpacingInVoxels ()
Public Member Functions inherited from vtkEncodedGradientEstimator
void	Update (void)
unsigned short *	GetEncodedNormals (void)
unsigned char *	GetGradientMagnitudes (void)
virtual int	GetUseCylinderClip ()
int *	GetCircleLimits ()
virtual int *	GetInputSize ()
virtual void	GetInputSize (int data[3])
virtual float *	GetInputAspect ()
virtual void	GetInputAspect (float data[3])
virtual void	SetInput (vtkImageData *)
virtual vtkImageData *	GetInput ()
virtual void	SetGradientMagnitudeScale (float)
virtual float	GetGradientMagnitudeScale ()
virtual void	SetGradientMagnitudeBias (float)
virtual float	GetGradientMagnitudeBias ()
virtual void	SetBoundsClip (int)
virtual int	GetBoundsClip ()
virtual void	BoundsClipOn ()
virtual void	BoundsClipOff ()
virtual void	SetBounds (int, int, int, int, int, int)
virtual void	SetBounds (int[6])
virtual int *	GetBounds ()
virtual void	GetBounds (int data[6])
int	GetEncodedNormalIndex (int xyz_index)
int	GetEncodedNormalIndex (int x_index, int y_index, int z_index)
virtual void	SetNumberOfThreads (int)
virtual int	GetNumberOfThreads ()
void	SetDirectionEncoder (vtkDirectionEncoder *direnc)
virtual vtkDirectionEncoder *	GetDirectionEncoder ()
virtual void	SetComputeGradientMagnitudes (int)
virtual int	GetComputeGradientMagnitudes ()
virtual void	ComputeGradientMagnitudesOn ()
virtual void	ComputeGradientMagnitudesOff ()
virtual void	SetCylinderClip (int)
virtual int	GetCylinderClip ()
virtual void	CylinderClipOn ()
virtual void	CylinderClipOff ()
virtual float	GetLastUpdateTimeInSeconds ()
virtual float	GetLastUpdateTimeInCPUSeconds ()
void	SetZeroNormalThreshold (float v)
virtual float	GetZeroNormalThreshold ()
virtual void	SetZeroPad (int)
virtual int	GetZeroPad ()
virtual void	ZeroPadOn ()
virtual void	ZeroPadOff ()
Public Member Functions inherited from vtkObject
virtual void	DebugOn ()
virtual void	DebugOff ()
unsigned char	GetDebug ()
void	SetDebug (unsigned char debugFlag)
virtual void	Modified ()
virtual unsigned long	GetMTime ()
unsigned long	AddObserver (unsigned long event, vtkCommand *, float priority=0.0f)
unsigned long	AddObserver (const char event, vtkCommand , float priority=0.0f)
vtkCommand *	GetCommand (unsigned long tag)
void	RemoveObserver (vtkCommand *)
void	RemoveObservers (unsigned long event, vtkCommand *)
void	RemoveObservers (const char event, vtkCommand )
int	HasObserver (unsigned long event, vtkCommand *)
int	HasObserver (const char event, vtkCommand )
void	RemoveObserver (unsigned long tag)
void	RemoveObservers (unsigned long event)
void	RemoveObservers (const char *event)
void	RemoveAllObservers ()
int	HasObserver (unsigned long event)
int	HasObserver (const char *event)
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::*callback)(), float priority=0.0f)
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::callback)(vtkObject , unsigned long, void *), float priority=0.0f)
int	InvokeEvent (unsigned long event, void *callData)
int	InvokeEvent (const char event, void callData)
int	InvokeEvent (unsigned long event)
int	InvokeEvent (const char *event)
Public Member Functions inherited from vtkObjectBase
const char *	GetClassName () const
virtual void	Delete ()
virtual void	FastDelete ()
void	Print (ostream &os)
virtual void	Register (vtkObjectBase *o)
virtual void	UnRegister (vtkObjectBase *o)
void	SetReferenceCount (int)
void	PrintRevisions (ostream &os)
virtual void	PrintHeader (ostream &os, vtkIndent indent)
virtual void	PrintTrailer (ostream &os, vtkIndent indent)
int	GetReferenceCount ()

Static Public Member Functions
static int	IsTypeOf (const char *type)
static vtkFiniteDifferenceGradientEstimator *	SafeDownCast (vtkObject *o)
static vtkFiniteDifferenceGradientEstimator *	New ()

Public Attributes
int	SampleSpacingInVoxels
Public Attributes inherited from vtkEncodedGradientEstimator
vtkImageData *	Input
unsigned short *	EncodedNormals
int	EncodedNormalsSize [3]
unsigned char *	GradientMagnitudes
vtkTimeStamp	BuildTime

Protected Member Functions
	vtkFiniteDifferenceGradientEstimator ()
	~vtkFiniteDifferenceGradientEstimator ()
Protected Member Functions inherited from vtkEncodedGradientEstimator
	vtkEncodedGradientEstimator ()
	~vtkEncodedGradientEstimator ()
virtual void	ReportReferences (vtkGarbageCollector *)
void	ComputeCircleLimits (int size)
Protected Member Functions inherited from vtkObject
	vtkObject ()
virtual	~vtkObject ()
virtual void	RegisterInternal (vtkObjectBase *, int check)
virtual void	UnRegisterInternal (vtkObjectBase *, int check)
void	InternalGrabFocus (vtkCommand mouseEvents, vtkCommand keypressEvents=NULL)
void	InternalReleaseFocus ()
Protected Member Functions inherited from vtkObjectBase
	vtkObjectBase ()
virtual	~vtkObjectBase ()
virtual void	CollectRevisions (ostream &os)
	vtkObjectBase (const vtkObjectBase &)
void	operator= (const vtkObjectBase &)
void	UpdateNormals (void)

Additional Inherited Members
Protected Attributes inherited from vtkEncodedGradientEstimator
int	NumberOfThreads
vtkMultiThreader *	Threader
vtkDirectionEncoder *	DirectionEncoder
float	GradientMagnitudeScale
float	GradientMagnitudeBias
float	LastUpdateTimeInSeconds
float	LastUpdateTimeInCPUSeconds
float	ZeroNormalThreshold
int	CylinderClip
int *	CircleLimits
int	CircleLimitsSize
int	UseCylinderClip
int	BoundsClip
int	Bounds [6]
int	InputSize [3]
float	InputAspect [3]
int	ComputeGradientMagnitudes
int	ZeroPad
Protected Attributes inherited from vtkObject
unsigned char	Debug
vtkTimeStamp	MTime
vtkSubjectHelper *	SubjectHelper
Protected Attributes inherited from vtkObjectBase
int	ReferenceCount
vtkWeakPointerBase **	WeakPointers

Detailed Description

Use finite differences to estimate gradient.

vtkFiniteDifferenceGradientEstimator is a concrete subclass of vtkEncodedGradientEstimator that uses a central differences technique to estimate the gradient. The gradient at some sample location (x,y,z) would be estimated by:

 nx = (f(x-dx,y,z) - f(x+dx,y,z)) / 2*dx;
 ny = (f(x,y-dy,z) - f(x,y+dy,z)) / 2*dy;
 nz = (f(x,y,z-dz) - f(x,y,z+dz)) / 2*dz;

This value is normalized to determine a unit direction vector and a magnitude. The normal is computed in voxel space, and dx = dy = dz = SampleSpacingInVoxels. A scaling factor is applied to convert this normal from voxel space to world coordinates.

See also:: vtkEncodedGradientEstimator

Tests:: vtkFiniteDifferenceGradientEstimator (Tests)

Definition at line 46 of file vtkFiniteDifferenceGradientEstimator.h.

Member Typedef Documentation

typedef vtkEncodedGradientEstimator vtkFiniteDifferenceGradientEstimator::Superclass

Reimplemented from vtkEncodedGradientEstimator.

Definition at line 49 of file vtkFiniteDifferenceGradientEstimator.h.

Constructor & Destructor Documentation

vtkFiniteDifferenceGradientEstimator::vtkFiniteDifferenceGradientEstimator ( )

protected

vtkFiniteDifferenceGradientEstimator::~vtkFiniteDifferenceGradientEstimator ( )

protected

Member Function Documentation

virtual const char* vtkFiniteDifferenceGradientEstimator::GetClassName ( )

virtual

Reimplemented from vtkEncodedGradientEstimator.

static int vtkFiniteDifferenceGradientEstimator::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 vtkEncodedGradientEstimator.

virtual int vtkFiniteDifferenceGradientEstimator::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 vtkEncodedGradientEstimator.

static vtkFiniteDifferenceGradientEstimator* vtkFiniteDifferenceGradientEstimator::SafeDownCast ( vtkObject * o )

static

Reimplemented from vtkEncodedGradientEstimator.

void vtkFiniteDifferenceGradientEstimator::PrintSelf	(	ostream &	os,
		vtkIndent	indent
	)

virtual

Methods invoked by print to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkEncodedGradientEstimator.

static vtkFiniteDifferenceGradientEstimator* vtkFiniteDifferenceGradientEstimator::New ( )

static

Construct a vtkFiniteDifferenceGradientEstimator with a SampleSpacingInVoxels of 1.

Reimplemented from vtkObject.

virtual void vtkFiniteDifferenceGradientEstimator::SetSampleSpacingInVoxels ( int )

virtual

Set/Get the spacing between samples for the finite differences method used to compute the normal. This spacing is in voxel units.

virtual int vtkFiniteDifferenceGradientEstimator::GetSampleSpacingInVoxels ( )

virtual

Set/Get the spacing between samples for the finite differences method used to compute the normal. This spacing is in voxel units.

void vtkFiniteDifferenceGradientEstimator::UpdateNormals ( void )

protectedvirtual

Recompute the encoded normals and gradient magnitudes.

Implements vtkEncodedGradientEstimator.

Member Data Documentation

int vtkFiniteDifferenceGradientEstimator::SampleSpacingInVoxels

Definition at line 60 of file vtkFiniteDifferenceGradientEstimator.h.

The documentation for this class was generated from the following file:

dox/VolumeRendering/vtkFiniteDifferenceGradientEstimator.h

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation