ITK
6.0.0
Insight Toolkit
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#include <itkCurvatureFlowImageFilter.h>
Denoise an image using curvature driven flow.
CurvatureFlowImageFilter implements a curvature driven image denoising algorithm. Iso-brightness contours in the grayscale input image are viewed as a level set. The level set is then evolved using a curvature-based speed function:
\[ I_t = \kappa |\nabla I| \]
where \( \kappa \) is the curvature.
The advantage of this approach is that sharp boundaries are preserved with smoothing occurring only within a region. However, it should be noted that continuous application of this scheme will result in the eventual removal of all information as each contour shrinks to zero and disappear.
Note that unlike level set segmentation algorithms, the image to be denoised is already the level set and can be set directly as the input using the SetInput() method.
This filter has two parameters: the number of update iterations to be performed and the timestep between each update.
The timestep should be "small enough" to ensure numerical stability. Stability is guarantee when the timestep meets the CFL (Courant-Friedrichs-Levy) condition. Broadly speaking, this condition ensures that each contour does not move more than one grid position at each timestep. In the literature, the timestep is typically user specified and have to manually tuned to the application.
This filter make use of the multi-threaded finite difference solver hierarchy. Updates are computed using a CurvatureFlowFunction object. A zero flux Neumann boundary condition when computing derivatives near the data boundary.
This filter may be streamed. To support streaming this filter produces a padded output which takes into account edge effects. The size of the padding is m_NumberOfIterations on each edge. Users of this filter should only make use of the center valid central region.
Reference: "Level Set Methods and Fast Marching Methods", J.A. Sethian, Cambridge Press, Chapter 16, Second edition, 1999.
Input/Output Restrictions: TInputImage and TOutputImage must have the same dimension. TOutputImage's pixel type must be a real number type.
Definition at line 96 of file itkCurvatureFlowImageFilter.h.
Static Public Member Functions | |
static Pointer | New () |
Static Public Member Functions inherited from itk::ImageToImageFilter< TInputImage, TOutputImage > | |
static double | GetGlobalDefaultCoordinateTolerance () |
static double | GetGlobalDefaultDirectionTolerance () |
static void | SetGlobalDefaultCoordinateTolerance (double) |
static void | SetGlobalDefaultDirectionTolerance (double) |
Static Public Member Functions inherited from itk::Object | |
static bool | GetGlobalWarningDisplay () |
static void | GlobalWarningDisplayOff () |
static void | GlobalWarningDisplayOn () |
static Pointer | New () |
static void | SetGlobalWarningDisplay (bool val) |
Static Public Member Functions inherited from itk::LightObject | |
static void | BreakOnError () |
static Pointer | New () |
Static Public Attributes | |
static constexpr unsigned int | ImageDimension = Superclass::ImageDimension |
Static Public Attributes inherited from itk::DenseFiniteDifferenceImageFilter< TInputImage, TOutputImage > | |
static constexpr unsigned int | ImageDimension = Superclass::ImageDimension |
Static Public Attributes inherited from itk::FiniteDifferenceImageFilter< TInputImage, TOutputImage > | |
static constexpr unsigned int | ImageDimension = OutputImageType::ImageDimension |
Static Public Attributes inherited from itk::InPlaceImageFilter< TInputImage, TOutputImage > | |
static constexpr unsigned int | InputImageDimension |
static constexpr unsigned int | OutputImageDimension |
Static Public Attributes inherited from itk::ImageToImageFilter< TInputImage, TOutputImage > | |
static constexpr unsigned int | InputImageDimension = TInputImage::ImageDimension |
static constexpr unsigned int | OutputImageDimension = TOutputImage::ImageDimension |
Static Public Attributes inherited from itk::ImageSource< TOutputImage > | |
static constexpr unsigned int | OutputImageDimension = TOutputImage::ImageDimension |
Private Attributes | |
TimeStepType | m_TimeStep {} |
using itk::CurvatureFlowImageFilter< TInputImage, TOutputImage >::ConstPointer = SmartPointer<const Self> |
Definition at line 106 of file itkCurvatureFlowImageFilter.h.
using itk::CurvatureFlowImageFilter< TInputImage, TOutputImage >::CurvatureFlowFunctionType = CurvatureFlowFunction<OutputImageType> |
CurvatureFlowFunction type.
Definition at line 125 of file itkCurvatureFlowImageFilter.h.
using itk::CurvatureFlowImageFilter< TInputImage, TOutputImage >::OutputImagePointer = typename OutputImageType::Pointer |
Definition at line 119 of file itkCurvatureFlowImageFilter.h.
using itk::CurvatureFlowImageFilter< TInputImage, TOutputImage >::Pointer = SmartPointer<Self> |
Definition at line 105 of file itkCurvatureFlowImageFilter.h.
using itk::CurvatureFlowImageFilter< TInputImage, TOutputImage >::Self = CurvatureFlowImageFilter |
Standard class type aliases.
Definition at line 103 of file itkCurvatureFlowImageFilter.h.
using itk::CurvatureFlowImageFilter< TInputImage, TOutputImage >::Superclass = DenseFiniteDifferenceImageFilter<TInputImage, TOutputImage> |
Definition at line 104 of file itkCurvatureFlowImageFilter.h.
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protected |
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overrideprotecteddefault |
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overrideprotectedvirtual |
To support streaming, this filter produces a output which is larger than the original requested region. The output is padding by m_NumberOfIterations pixels on edge.
Reimplemented from itk::ProcessObject.
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overrideprotectedvirtual |
Edge effects are taken care of by padding the output requested region. As such, the input requested region needs to at minimum the same size as the output requested region.
Reimplemented from itk::FiniteDifferenceImageFilter< TInputImage, TOutputImage >.
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overridevirtual |
Reimplemented from itk::DenseFiniteDifferenceImageFilter< TInputImage, TOutputImage >.
Reimplemented in itk::MinMaxCurvatureFlowImageFilter< TInputImage, TOutputImage >.
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virtual |
Get the timestep parameter.
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inlineoverrideprotectedvirtual |
Supplies the halting criteria for this class of filters. The algorithm will stop after a user-specified number of iterations.
Reimplemented from itk::FiniteDifferenceImageFilter< TInputImage, TOutputImage >.
Definition at line 165 of file itkCurvatureFlowImageFilter.h.
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overrideprotectedvirtual |
Initialize the state of filter and equation before each iteration. Progress feedback is implemented as part of this method.
Reimplemented from itk::FiniteDifferenceImageFilter< TInputImage, TOutputImage >.
Reimplemented in itk::MinMaxCurvatureFlowImageFilter< TInputImage, TOutputImage >.
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static |
Method for creation through the object factory.
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overrideprotectedvirtual |
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 itk::DenseFiniteDifferenceImageFilter< TInputImage, TOutputImage >.
Reimplemented in itk::MinMaxCurvatureFlowImageFilter< TInputImage, TOutputImage >.
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virtual |
Set the timestep parameter.
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staticconstexpr |
Dimensionality of input and output data is assumed to be the same. It is inherited from the superclass.
Definition at line 129 of file itkCurvatureFlowImageFilter.h.
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private |
Definition at line 196 of file itkCurvatureFlowImageFilter.h.