template<class TInputImage, class TClassifiedImage>
class itk::MRFImageFilter< TInputImage, TClassifiedImage >
Implementation of a labeller object that uses Markov Random Fields to classify pixels in an image data set.
This object classifies pixels based on a Markov Random Field (MRF) model. This implementation uses the maximum a posteriori (MAP) estimates for modeling the MRF. The object traverses the data set and uses the model generated by the Mahalanobis distance classifier to get the distance between each pixel in the data set to a set of known classes, updates the distances by evaluating the influence of its neighboring pixels (based on a MRF model) and finally, classifies each pixel to the class which has the minimum distance to that pixel (taking the neighborhood influence under consideration). DoNeighborhoodOperation is the function that can be modified to achieve different falvors of MRF filters in derived classes.
The classified initial labeled image is needed. It is important that the number of expected classes be set before calling the classifier. In our case we have used the ImageClassifer using a Gaussian model to generate the initial labels. This classifier requires the user to ensure that an appropriate membership function is provided. See the documentation of the image classifier class for more information.
The influence of a neighborhood on a given pixel's classification (the MRF term) is computed by calculating a weighted sum of number of class labels in a three dimensional neighborhood. The basic idea of this neighborhood influence is that if a large number of neighbors of a pixel are of one class, then the current pixel is likely to be of the same class.
The dimensions of the neighborhood are the same as the input image dimensions, and values of the weighting parameters are either specified by the user or through the beta matrix parameter. The default weighting table is generated during object construction. The following table shows an example of a 3 x 3 x 3 neighborhood and the weighting values used. A 3 x 3 x 3 kernel is used where each value is a nonnegative parameter, which encourages neighbors to be of the same class. In this example, the influence of the pixels in the same slice is assigned a weight 1.7. The influence of the pixels in the same location in the previous and next slice is assigned a weight 1.5. A weight of 1.3 is assigned to the influence of the north, south, east, west, and diagonal pixels in the previous and next slices.
![\[\begin{tabular}{ccc} \begin{tabular}{|c|c|c|} 1.3 & 1.3 & 1.3 \\ 1.3 & 1.5 & 1.3 \\ 1.3 & 1.3 & 1.3 \\ \end{tabular} & \begin{tabular}{|c|c|c|} 1.7 & 1.7 & 1.7 \\ 1.7 & 0 & 1.7 \\ 1.7 & 1.7 & 1.7 \\ \end{tabular} & \begin{tabular}{|c|c|c|} 1.3 & 1.3 & 1.3 \\ 1.5 & 1.5 & 1.3 \\ 1.3 & 1.3 & 1.3 \\ \end{tabular} \\ \end{tabular}\]](form_359.png)
The user needs to set the neighborhood size using the SetNeighborhoodRadius function. The details on the semantics of a neighborhood can be found in the documentation associated with the itkNeighborhood and related objects. NOTE: The size of the neighborhood must match the size of the neighborhood weighting parameters set by the user.
For minimization of the MRF labeling function the MinimizeFunctional virtual method is called. For our current implementation we use the iterated conditional modes (ICM) algorithm described by Besag in the paper ``On the Statistical Analysis of Dirty Pictures'' in J. Royal Stat. Soc. B, Vol. 48, 1986.
In each iteration, the algorithm visits each pixel in turn and determines whether to update its classification by computing the influence of the classification of the pixel's neighbors and of the intensity data. On each iteration after the first, we reexamine the classification of a pixel only if the classification of some of its neighbors has changed in the previous iteration. The pixels' classification is updated using a synchronous scheme (iteration by iteration) until the error reaches less than the threshold or the number of iteration exceed the maximum set number of iterations. Note: The current implementation supports betaMatrix default weight for two and three dimensional images only. The default for higher dimension is set to unity. This should be overridden by custom weights after filter initialization.
- See Also
- Neighborhood
-
ImageIterator
-
NeighborhoodIterator
-
Classifier
Definition at line 125 of file itkMRFImageFilter.h.
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| virtual ::itk::LightObject::Pointer | CreateAnother (void) const |
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| virtual std::vector< double > | GetMRFNeighborhoodWeight () |
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| virtual const char * | GetNameOfClass () const |
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| const NeighborhoodRadiusType | GetNeighborhoodRadius () const |
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| virtual const unsigned int & | GetNumberOfIterations () |
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| virtual const StopConditionType & | GetStopCondition () |
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| void | SetClassifier (typename ClassifierType::Pointer ptrToClassifier) |
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| virtual void | SetMRFNeighborhoodWeight (std::vector< double > BetaMatrix) |
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| void | SetNeighborhoodRadius (const NeighborhoodRadiusType &) |
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| void | SetNeighborhoodRadius (const SizeValueType) |
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| void | SetNeighborhoodRadius (const SizeValueType *radiusArray) |
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| | typedef (Concept::Convertible< unsigned int, LabelledImagePixelType >) UnsignedIntConvertibleToClassifiedCheck |
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| | typedef (Concept::Convertible< LabelledImagePixelType, unsigned int >) ClassifiedConvertibleToUnsignedIntCheck |
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| | typedef (Concept::Convertible< LabelledImagePixelType, int >) ClassifiedConvertibleToIntCheck |
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| | typedef (Concept::Convertible< int, LabelledImagePixelType >) IntConvertibleToClassifiedCheck |
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| | typedef (Concept::SameDimension< InputImageDimension, ClassifiedImageDimension >) SameDimensionCheck |
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| virtual void | SetNumberOfClasses (unsigned int _arg) |
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| virtual unsigned int | GetNumberOfClasses () const |
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| virtual void | SetMaximumNumberOfIterations (unsigned int _arg) |
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| virtual unsigned int | GetMaximumNumberOfIterations () const |
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| virtual void | SetErrorTolerance (double _arg) |
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| virtual double | GetErrorTolerance () const |
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| virtual void | SetSmoothingFactor (double _arg) |
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| virtual double | GetSmoothingFactor () const |
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| const InputImageType * | GetInput (void) const |
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| const InputImageType * | GetInput (unsigned int idx) const |
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| virtual void | PopBackInput () |
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| virtual void | PopFrontInput () |
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| virtual void | PushBackInput (const InputImageType *image) |
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| virtual void | PushFrontInput (const InputImageType *image) |
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| virtual void | SetInput (const InputImageType *image) |
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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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| virtual void | GraftNthOutput (unsigned int idx, DataObject *output) |
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| virtual void | GraftOutput (DataObject *output) |
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| virtual void | GraftOutput (const DataObjectIdentifierType &key, DataObject *output) |
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| OutputImageType * | GetOutput (void) |
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| const OutputImageType * | GetOutput (void) const |
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virtual
ProcessObject::DataObjectPointer | MakeOutput (ProcessObject::DataObjectPointerArraySizeType idx) |
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| virtual void | AbortGenerateDataOff () |
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| virtual void | AbortGenerateDataOn () |
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| virtual const bool & | GetAbortGenerateData () |
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| NameArray | GetInputNames () const |
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| MultiThreader * | GetMultiThreader () const |
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| DataObjectPointerArraySizeType | GetNumberOfIndexedInputs () 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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| virtual const float & | GetProgress () |
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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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| virtual DataObjectPointer | MakeOutput (const DataObjectIdentifierType &) |
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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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| virtual void | SetProgress (float _arg) |
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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 amount) |
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| DataObjectPointerArray | GetInputs () |
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| DataObjectPointerArray | GetOutputs () |
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| DataObjectPointerArray | GetIndexedInputs () |
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| DataObjectPointerArray | GetIndexedOutputs () |
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| DataObjectPointerArraySizeType | GetNumberOfIndexedOutputs () const |
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| virtual void | SetReleaseDataFlag (bool flag) |
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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 () |
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| virtual void | ReleaseDataBeforeUpdateFlagOn () |
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| virtual void | ReleaseDataBeforeUpdateFlagOff () |
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| virtual void | SetNumberOfThreads (ThreadIdType _arg) |
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| virtual const ThreadIdType & | GetNumberOfThreads () |
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| unsigned long | AddObserver (const EventObject &event, Command *) |
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| unsigned long | AddObserver (const EventObject &event, Command *) const |
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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 (void) |
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| const MetaDataDictionary & | GetMetaDataDictionary (void) 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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| virtual void | Register () const |
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| void | RemoveAllObservers () |
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| void | RemoveObserver (unsigned long tag) |
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| void | SetDebug (bool debugFlag) const |
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| void | SetMetaDataDictionary (const MetaDataDictionary &rhs) |
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| virtual void | SetReferenceCount (int) |
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| virtual void | UnRegister () const |
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| virtual void | Delete () |
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| virtual int | GetReferenceCount () const |
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| | itkCloneMacro (Self) |
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| void | Print (std::ostream &os, Indent indent=0) const |
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| void | Allocate () |
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| virtual void | ApplyMRFImageFilter () |
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| virtual void | DoNeighborhoodOperation (const InputImageNeighborhoodIterator &imageIter, LabelledImageNeighborhoodIterator &labelledIter, LabelStatusImageNeighborhoodIterator &labelStatusIter) |
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| virtual void | EnlargeOutputRequestedRegion (DataObject *) |
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| virtual void | GenerateData () |
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| virtual void | GenerateInputRequestedRegion () |
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| virtual void | GenerateOutputInformation () |
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| virtual void | MinimizeFunctional () |
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| | MRFImageFilter () |
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| void | PrintSelf (std::ostream &os, Indent indent) const |
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| | ~MRFImageFilter () |
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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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| virtual void | VerifyInputInformation () |
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| | ~ImageToImageFilter () |
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| void | PushBackInput (const DataObject *input) |
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| void | PushFrontInput (const DataObject *input) |
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| virtual void | AfterThreadedGenerateData () |
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| virtual void | AllocateOutputs () |
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| virtual void | BeforeThreadedGenerateData () |
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virtual const
ImageRegionSplitterBase * | GetImageRegionSplitter (void) const |
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| | ImageSource () |
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| virtual unsigned int | SplitRequestedRegion (unsigned int i, unsigned int num, OutputImageRegionType &splitRegion) |
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| virtual void | ThreadedGenerateData (const OutputImageRegionType &outputRegionForThread, ThreadIdType threadId) |
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| virtual | ~ImageSource () |
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| virtual void | AddInput (DataObject *input) |
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| virtual void | AddOutput (DataObject *output) |
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| virtual void | CacheInputReleaseDataFlags () |
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| virtual void | GenerateOutputRequestedRegion (DataObject *output) |
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virtual const
DataObjectPointerArraySizeType & | GetNumberOfRequiredOutputs () |
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| bool | IsIndexedInputName (const DataObjectIdentifierType &) const |
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| bool | IsIndexedOutputName (const DataObjectIdentifierType &) const |
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| | itkLegacyMacro (virtual void RemoveOutput(DataObject *output)) |
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| | itkLegacyMacro (void SetNumberOfOutputs(DataObjectPointerArraySizeType num)) |
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| | itkLegacyMacro (virtual void RemoveInput(DataObject *input)) |
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| | itkLegacyMacro (void SetNumberOfInputs(DataObjectPointerArraySizeType num)) |
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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 | 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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| virtual void | RestoreInputReleaseDataFlags () |
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| virtual void | SetInput (const DataObjectIdentifierType &key, DataObject *input) |
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| virtual void | SetNthInput (DataObjectPointerArraySizeType num, DataObject *input) |
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| virtual void | SetNthOutput (DataObjectPointerArraySizeType num, DataObject *output) |
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| void | SetNumberOfIndexedInputs (DataObjectPointerArraySizeType num) |
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| void | SetNumberOfIndexedOutputs (DataObjectPointerArraySizeType num) |
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| virtual void | SetNumberOfRequiredOutputs (DataObjectPointerArraySizeType _arg) |
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| virtual void | SetOutput (const DataObjectIdentifierType &key, DataObject *output) |
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| virtual void | SetPrimaryInput (DataObject *input) |
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| virtual void | SetPrimaryOutput (DataObject *output) |
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| virtual void | VerifyPreconditions () |
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| | ~ProcessObject () |
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| DataObject * | GetInput (const DataObjectIdentifierType &key) |
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| const DataObject * | GetInput (const DataObjectIdentifierType &key) const |
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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 (void) const |
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| virtual void | SetNumberOfRequiredInputs (DataObjectPointerArraySizeType) |
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virtual const
DataObjectPointerArraySizeType & | GetNumberOfRequiredInputs () |
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| bool | AddRequiredInputName (const DataObjectIdentifierType &) |
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| bool | AddRequiredInputName (const DataObjectIdentifierType &, DataObjectPointerArraySizeType idx) |
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| bool | RemoveRequiredInputName (const DataObjectIdentifierType &) |
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| bool | IsRequiredInputName (const DataObjectIdentifierType &) const |
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| void | SetRequiredInputNames (const NameArray &) |
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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 (void) const |
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| DataObject * | GetOutput (DataObjectPointerArraySizeType idx) |
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| const DataObject * | GetOutput (DataObjectPointerArraySizeType idx) const |
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| DataObject * | GetPrimaryOutput () |
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| const DataObject * | GetPrimaryOutput () const |
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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 &time) |
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| virtual | ~Object () |
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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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Inheritance diagram for itk::MRFImageFilter< TInputImage, TClassifiedImage >:
1.8.3.1
