template<typename TInputImage, typename TRealType = float, typename TOutputImage = Image<TRealType, TInputImage::ImageDimension>>
class itk::VectorGradientMagnitudeImageFilter< TInputImage, TRealType, TOutputImage >
Computes a scalar, gradient magnitude image from a multiple channel (pixels are vectors) input.
- Overview
- This filter has two calculation modes. The first (default) mode calculates gradient magnitude as the difference between the largest two singular values in a singular value decomposition (SVD) of the partial derivatives [1]. The gradient is then based on the direction of maximal change, and is a characterization of how "elongated" the point-spread of the analysis is found to be.
The second, more heuristic, calculation mode finds gradient magnitude as the square-root of the sum of the * individual weighted vector component derivative sums squared. That is, * \( \mathbf{magnitude} = \left( \sum_{i=0}^n \sum_{j=0}^m \frac{\delta * \phi_j}{\delta \mathbf{x}_{i}}^2 \right)^{\frac{1}{2}} \), where \(\phi_j\) * is the \(j^{\mathbf{th}}\) channel of vector image \(\phi\) of dimension \(n\). * Weighting terms are applied to each vector component.
The second mode is computationally much faster than the first and has the advantage that it is automatically multi-threaded (some vnl functions used in the first mode are not thread-safe). The first mode, however, tends to give intuitively better results with less (or no) parameter tuning.
- Template Parameters (Input and Output)
- This filter has one required template parameter which defines the input image type. The pixel type of the input image is assumed to be a vector (e.g., itk::Vector, itk::FixedArray). The scalar type of the vector components must be castable to floating point. Instantiating with an image of RGBPixel is not allowed but the image can be converted/adapted to Vector for processing.
The second template parameter, TRealType, can be optionally specified to define the scalar numerical type used in calculations. This is the component type of the output image. The default type of TRealType is float. For extra precision, you may safely change this parameter to double.
The third template parameter is the output image type. The third parameter will be automatically constructed from the first and second parameters, so it is not necessary (or advisable) to set this parameter explicitly. Given an M-channel input image with dimensionality N, and a numerical type specified as TRealType, the output image will be of type itk::Image<TRealType, N>.
- Filter Parameters
- The methods Set/GetUsePrincipleComponents and SetUsePrincipleComponentsOn/Off determine controls the calculation mode that is used.
The method UseImageSpacingOn will cause derivatives in the image to be scaled (inversely) with the pixel size of the input image, effectively taking derivatives in world coordinates (versus isotropic image space). UseImageSpacingOff turns this functionality off. Default is UseImageSpacingOn. The parameter UseImageSpacing can be set directly with the method SetUseImageSpacing(bool).
Weights can be applied to the derivatives directly using the SetDerivativeWeights method. Note that if UseImageSpacing is set to TRUE (ON), then these weights will be overridden by weights derived from the image spacing when the filter is updated. The argument to this method is a C array of TRealValue type.
Weights can be applied to each vector component of the image when the component derivative values are summed during computation. Specify these weights using the SetComponentWeights method. The argument to this method is a C array of TRealValue type. /**
- Examples
- Examples/IO/VisibleHumanPasteWrite.cxx, and Examples/Segmentation/WatershedSegmentation1.cxx.
Definition at line 138 of file itkVectorGradientMagnitudeImageFilter.h.
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void | GenerateInputRequestedRegion () override |
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| ITK_DISALLOW_COPY_AND_MOVE (VectorGradientMagnitudeImageFilter) |
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| itkConceptMacro (InputHasNumericTraitsCheck,(Concept::HasNumericTraits< typename InputPixelType::ValueType >)) |
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| itkConceptMacro (RealTypeHasNumericTraitsCheck,(Concept::HasNumericTraits< RealType >)) |
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| itkConceptMacro (SameDimensionCheck,(Concept::SameDimension< InputImageDimension, ImageDimension >)) |
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| itkNewMacro (Self) |
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| itkOverrideGetNameOfClassMacro (VectorGradientMagnitudeImageFilter) |
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void | SetUseImageSpacingOff () |
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void | SetUseImageSpacingOn () |
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void | SetUsePrincipleComponentsOff () |
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void | SetUsePrincipleComponentsOn () |
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void | SetUseImageSpacing (bool) |
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| itkGetConstMacro (UseImageSpacing, bool) |
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| itkBooleanMacro (UseImageSpacing) |
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| itkSetMacro (DerivativeWeights, DerivativeWeightsType) |
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| itkGetConstReferenceMacro (DerivativeWeights, DerivativeWeightsType) |
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| itkSetMacro (ComponentWeights, ComponentWeightsType) |
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| itkGetConstReferenceMacro (ComponentWeights, ComponentWeightsType) |
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| itkSetMacro (UsePrincipleComponents, bool) |
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| itkGetConstMacro (UsePrincipleComponents, bool) |
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| itkBooleanMacro (UsePrincipleComponents) |
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const InputImageType * | GetInput () const |
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const InputImageType * | GetInput (unsigned int idx) const |
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const char * | GetNameOfClass () const override |
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void | PopBackInput () override |
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void | PopFrontInput () override |
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virtual void | PushBackInput (const InputImageType *input) |
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virtual void | PushFrontInput (const InputImageType *input) |
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virtual void | SetInput (const DataObjectIdentifierType &key, DataObject *input) |
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virtual void | SetInput (const InputImageType *input) |
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virtual void | SetInput (unsigned int, const TInputImage *image) |
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virtual void | SetCoordinateTolerance (double _arg) |
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virtual double | GetCoordinateTolerance () const |
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virtual void | SetDirectionTolerance (double _arg) |
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virtual double | GetDirectionTolerance () const |
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OutputImageType * | GetOutput (unsigned int idx) |
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OutputImageType * | GetOutput () |
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const OutputImageType * | GetOutput () const |
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virtual void | GraftOutput (DataObject *graft) |
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virtual void | GraftOutput (const DataObjectIdentifierType &key, DataObject *graft) |
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virtual void | GraftNthOutput (unsigned int idx, DataObject *graft) |
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ProcessObject::DataObjectPointer | MakeOutput (ProcessObject::DataObjectPointerArraySizeType idx) override |
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ProcessObject::DataObjectPointer | MakeOutput (const ProcessObject::DataObjectIdentifierType &) override |
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virtual void | AbortGenerateDataOn () |
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virtual void | EnlargeOutputRequestedRegion (DataObject *) |
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virtual const bool & | GetAbortGenerateData () const |
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DataObjectPointerArray | GetIndexedInputs () |
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DataObjectPointerArray | GetIndexedOutputs () |
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NameArray | GetInputNames () const |
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DataObjectPointerArray | GetInputs () |
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MultiThreaderType * | GetMultiThreader () const |
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const char * | GetNameOfClass () const override |
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DataObjectPointerArraySizeType | GetNumberOfIndexedInputs () const |
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DataObjectPointerArraySizeType | GetNumberOfIndexedOutputs () const |
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DataObjectPointerArraySizeType | GetNumberOfInputs () const |
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DataObjectPointerArraySizeType | GetNumberOfOutputs () const |
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virtual DataObjectPointerArraySizeType | GetNumberOfValidRequiredInputs () const |
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NameArray | GetOutputNames () const |
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DataObjectPointerArray | GetOutputs () |
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virtual float | GetProgress () const |
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NameArray | GetRequiredInputNames () const |
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bool | HasInput (const DataObjectIdentifierType &key) const |
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bool | HasOutput (const DataObjectIdentifierType &key) const |
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void | IncrementProgress (float increment) |
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virtual void | PrepareOutputs () |
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virtual void | PropagateRequestedRegion (DataObject *output) |
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virtual void | ResetPipeline () |
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virtual void | SetAbortGenerateData (bool _arg) |
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void | SetMultiThreader (MultiThreaderType *threader) |
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virtual void | Update () |
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virtual void | UpdateLargestPossibleRegion () |
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virtual void | UpdateOutputData (DataObject *output) |
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virtual void | UpdateOutputInformation () |
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void | UpdateProgress (float progress) |
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virtual void | SetReleaseDataFlag (bool val) |
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virtual bool | GetReleaseDataFlag () const |
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void | ReleaseDataFlagOn () |
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void | ReleaseDataFlagOff () |
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virtual void | SetReleaseDataBeforeUpdateFlag (bool _arg) |
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virtual const bool & | GetReleaseDataBeforeUpdateFlag () const |
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virtual void | ReleaseDataBeforeUpdateFlagOn () |
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virtual void | SetNumberOfWorkUnits (ThreadIdType _arg) |
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virtual const ThreadIdType & | GetNumberOfWorkUnits () const |
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unsigned long | AddObserver (const EventObject &event, Command *cmd) const |
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unsigned long | AddObserver (const EventObject &event, std::function< void(const EventObject &)> function) const |
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LightObject::Pointer | CreateAnother () const override |
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virtual void | DebugOff () const |
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virtual void | DebugOn () const |
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Command * | GetCommand (unsigned long tag) |
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bool | GetDebug () const |
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MetaDataDictionary & | GetMetaDataDictionary () |
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const MetaDataDictionary & | GetMetaDataDictionary () const |
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virtual ModifiedTimeType | GetMTime () const |
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virtual const TimeStamp & | GetTimeStamp () const |
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bool | HasObserver (const EventObject &event) const |
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void | InvokeEvent (const EventObject &) |
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void | InvokeEvent (const EventObject &) const |
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virtual void | Modified () const |
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void | Register () const override |
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void | RemoveAllObservers () |
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void | RemoveObserver (unsigned long tag) const |
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void | SetDebug (bool debugFlag) const |
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void | SetReferenceCount (int) override |
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void | UnRegister () const noexcept override |
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void | SetMetaDataDictionary (const MetaDataDictionary &rhs) |
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void | SetMetaDataDictionary (MetaDataDictionary &&rrhs) |
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virtual void | SetObjectName (std::string _arg) |
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virtual const std::string & | GetObjectName () const |
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Pointer | Clone () const |
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virtual void | Delete () |
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virtual int | GetReferenceCount () const |
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void | Print (std::ostream &os, Indent indent=0) const |
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void | BeforeThreadedGenerateData () override |
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void | DynamicThreadedGenerateData (const OutputImageRegionType &outputRegionForThread) override |
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TRealType | EvaluateAtNeighborhood (const ConstNeighborhoodIteratorType &it) const |
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TRealType | EvaluateAtNeighborhood3D (const ConstNeighborhoodIteratorType &it) const |
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| itkGetConstObjectMacro (RealValuedInputImage, RealVectorImageType) |
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TRealType | NonPCEvaluateAtNeighborhood (const ConstNeighborhoodIteratorType &it) const |
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void | PrintSelf (std::ostream &os, Indent indent) const override |
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| VectorGradientMagnitudeImageFilter () |
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| ~VectorGradientMagnitudeImageFilter () override=default |
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virtual void | CallCopyInputRegionToOutputRegion (OutputImageRegionType &destRegion, const InputImageRegionType &srcRegion) |
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virtual void | CallCopyOutputRegionToInputRegion (InputImageRegionType &destRegion, const OutputImageRegionType &srcRegion) |
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| ImageToImageFilter () |
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void | VerifyInputInformation () const override |
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| ~ImageToImageFilter () override=default |
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virtual void | PushBackInput (const DataObject *input) |
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virtual void | PushFrontInput (const DataObject *input) |
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virtual void | AfterThreadedGenerateData () |
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virtual void | AllocateOutputs () |
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void | ClassicMultiThread (ThreadFunctionType callbackFunction) |
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void | GenerateData () override |
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virtual const ImageRegionSplitterBase * | GetImageRegionSplitter () const |
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| ImageSource () |
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virtual unsigned int | SplitRequestedRegion (unsigned int i, unsigned int pieces, OutputImageRegionType &splitRegion) |
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| ~ImageSource () override=default |
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virtual void | ThreadedGenerateData (const OutputImageRegionType ®ion, ThreadIdType threadId) |
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virtual bool | GetDynamicMultiThreading () const |
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virtual void | SetDynamicMultiThreading (bool _arg) |
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virtual void | DynamicMultiThreadingOn () |
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virtual void | AddInput (DataObject *input) |
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void | AddOptionalInputName (const DataObjectIdentifierType &) |
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void | AddOptionalInputName (const DataObjectIdentifierType &, DataObjectPointerArraySizeType idx) |
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virtual void | AddOutput (DataObject *output) |
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bool | AddRequiredInputName (const DataObjectIdentifierType &) |
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bool | AddRequiredInputName (const DataObjectIdentifierType &, DataObjectPointerArraySizeType idx) |
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virtual void | CacheInputReleaseDataFlags () |
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virtual void | GenerateOutputInformation () |
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virtual void | GenerateOutputRequestedRegion (DataObject *output) |
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DataObject * | GetInput (const DataObjectIdentifierType &key) |
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const DataObject * | GetInput (const DataObjectIdentifierType &key) const |
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virtual const DataObjectPointerArraySizeType & | GetNumberOfRequiredInputs () const |
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virtual const DataObjectPointerArraySizeType & | GetNumberOfRequiredOutputs () const |
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bool | IsIndexedInputName (const DataObjectIdentifierType &) const |
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bool | IsIndexedOutputName (const DataObjectIdentifierType &) const |
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bool | IsRequiredInputName (const DataObjectIdentifierType &) const |
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DataObjectPointerArraySizeType | MakeIndexFromInputName (const DataObjectIdentifierType &name) const |
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DataObjectPointerArraySizeType | MakeIndexFromOutputName (const DataObjectIdentifierType &name) const |
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DataObjectIdentifierType | MakeNameFromInputIndex (DataObjectPointerArraySizeType idx) const |
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DataObjectIdentifierType | MakeNameFromOutputIndex (DataObjectPointerArraySizeType idx) const |
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| ProcessObject () |
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virtual void | PropagateResetPipeline () |
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virtual void | PushBackInput (const DataObject *input) |
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virtual void | PushFrontInput (const DataObject *input) |
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virtual void | ReleaseInputs () |
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virtual void | RemoveInput (const DataObjectIdentifierType &key) |
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virtual void | RemoveInput (DataObjectPointerArraySizeType) |
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virtual void | RemoveOutput (const DataObjectIdentifierType &key) |
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virtual void | RemoveOutput (DataObjectPointerArraySizeType idx) |
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bool | RemoveRequiredInputName (const DataObjectIdentifierType &) |
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virtual void | RestoreInputReleaseDataFlags () |
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virtual void | SetInput (const DataObjectIdentifierType &key, DataObject *input) |
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virtual void | SetNthInput (DataObjectPointerArraySizeType idx, DataObject *input) |
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virtual void | SetNthOutput (DataObjectPointerArraySizeType idx, DataObject *output) |
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void | SetNumberOfIndexedInputs (DataObjectPointerArraySizeType num) |
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void | SetNumberOfIndexedOutputs (DataObjectPointerArraySizeType num) |
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virtual void | SetNumberOfRequiredInputs (DataObjectPointerArraySizeType) |
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virtual void | SetNumberOfRequiredOutputs (DataObjectPointerArraySizeType _arg) |
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virtual void | SetOutput (const DataObjectIdentifierType &name, DataObject *output) |
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virtual void | SetPrimaryInput (DataObject *object) |
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virtual void | SetPrimaryOutput (DataObject *object) |
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void | SetRequiredInputNames (const NameArray &) |
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virtual void | VerifyPreconditions () const |
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| ~ProcessObject () override |
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DataObject * | GetInput (DataObjectPointerArraySizeType idx) |
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const DataObject * | GetInput (DataObjectPointerArraySizeType idx) const |
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DataObject * | GetPrimaryInput () |
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const DataObject * | GetPrimaryInput () const |
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virtual void | SetPrimaryInputName (const DataObjectIdentifierType &key) |
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virtual const char * | GetPrimaryInputName () const |
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DataObject * | GetOutput (const DataObjectIdentifierType &key) |
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const DataObject * | GetOutput (const DataObjectIdentifierType &key) const |
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virtual void | SetPrimaryOutputName (const DataObjectIdentifierType &key) |
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virtual const char * | GetPrimaryOutputName () const |
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DataObject * | GetOutput (DataObjectPointerArraySizeType i) |
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const DataObject * | GetOutput (DataObjectPointerArraySizeType i) const |
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DataObject * | GetPrimaryOutput () |
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const DataObject * | GetPrimaryOutput () const |
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virtual bool | GetThreaderUpdateProgress () const |
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virtual void | ThreaderUpdateProgressOn () |
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virtual void | SetThreaderUpdateProgress (bool arg) |
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| Object () |
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bool | PrintObservers (std::ostream &os, Indent indent) const |
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virtual void | SetTimeStamp (const TimeStamp &timeStamp) |
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| ~Object () override |
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virtual LightObject::Pointer | InternalClone () const |
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| LightObject () |
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virtual void | PrintHeader (std::ostream &os, Indent indent) const |
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virtual void | PrintTrailer (std::ostream &os, Indent indent) const |
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virtual | ~LightObject () |
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