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/*=========================================================================
*
* Copyright NumFOCUS
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#ifndef itkShapeDetectionLevelSetFunction_h
#define itkShapeDetectionLevelSetFunction_h
#include "itkSegmentationLevelSetFunction.h"
namespace itk
{
/** \class ShapeDetectionLevelSetFunction
*
* \brief This function is used in the ShapeDetectionLevelSetImageFilter to
* segment structures in an image based on a user supplied edge potential map.
*
* \par IMPORTANT
* The LevelSetFunction class contain additional information necessary
* to gain full understanding of how to use this function.
*
* ShapeDetectionLevelSetFunction is a subclass of the generic LevelSetFunction.
* It is used to segment structures in an image based on a user supplied
* edge potential map \f$ g(I) \f$, which
* has values close to zero in regions near edges (or high image gradient) and values
* close to one in regions with relatively constant intensity. Typically, the edge
* potential map is a function of the image gradient, for example:
*
* \f[ g(I) = 1 / ( 1 + | (\nabla * G)(I)| ) \f]
* \f[ g(I) = \exp^{-|(\nabla * G)(I)|} \f]
*
* where \f$ I \f$ is image intensity and
* \f$ (\nabla * G) \f$ is the derivative of Gaussian operator.
*
* The edge potential image is set via the SetFeatureImage() method.
*
* In this function both the propagation term \f$ P(\mathbf{x}) \f$
* and the curvature spatial modifier term \f$ Z(\mathbf{x}) \f$ are taken directly
* from the edge potential image such that:
*
* \f[ P(\mathbf{x}) = g(\mathbf{x}) \f]
* \f[ Z(\mathbf{x}) = g(\mathbf{x}) \f]
*
* Note that there is no advection term in this function.
*
* This implementation is based on:
* "Shape Modeling with Front Propagation: A Level Set Approach",
* R. Malladi, J. A. Sethian and B. C. Vermuri.
* IEEE Trans. on Pattern Analysis and Machine Intelligence,
* Vol 17, No. 2, pp 158-174, February 1995
*
* \sa LevelSetFunction
* \sa SegmentationLevelSetImageFunction
* \sa ShapeDetectionLevelSetImageFilter
*
* \ingroup FiniteDifferenceFunctions
* \ingroup ITKLevelSets
*/
template <typename TImageType, typename TFeatureImageType = TImageType>
class ITK_TEMPLATE_EXPORT ShapeDetectionLevelSetFunction
: public SegmentationLevelSetFunction<TImageType, TFeatureImageType>
{
public:
ITK_DISALLOW_COPY_AND_MOVE(ShapeDetectionLevelSetFunction);
/** Standard class type aliases. */
using Self = ShapeDetectionLevelSetFunction;
using Superclass = SegmentationLevelSetFunction<TImageType, TFeatureImageType>;
using Pointer = SmartPointer<Self>;
using ConstPointer = SmartPointer<const Self>;
using FeatureImageType = TFeatureImageType;
/** Method for creation through the object factory. */
itkNewMacro(Self);
/** \see LightObject::GetNameOfClass() */
itkOverrideGetNameOfClassMacro(ShapeDetectionLevelSetFunction);
/** Extract some parameters from the superclass. */
using typename Superclass::ImageType;
using typename Superclass::NeighborhoodType;
using typename Superclass::ScalarValueType;
using typename Superclass::FeatureScalarType;
using typename Superclass::RadiusType;
using typename Superclass::FloatOffsetType;
using typename Superclass::GlobalDataStruct;
/** Extract some parameters from the superclass. */
static constexpr unsigned int ImageDimension = Superclass::ImageDimension;
void
CalculateSpeedImage() override;
/** The curvature speed is same as the propagation speed. */
ScalarValueType
CurvatureSpeed(const NeighborhoodType & neighborhood,
const FloatOffsetType & offset,
GlobalDataStruct * gd) const override
{
return this->PropagationSpeed(neighborhood, offset, gd);
}
void
Initialize(const RadiusType & r) override
{
Superclass::Initialize(r);
this->SetAdvectionWeight(ScalarValueType{});
this->SetPropagationWeight(NumericTraits<ScalarValueType>::OneValue());
this->SetCurvatureWeight(NumericTraits<ScalarValueType>::OneValue());
}
protected:
ShapeDetectionLevelSetFunction()
{
this->SetAdvectionWeight(ScalarValueType{});
this->SetPropagationWeight(NumericTraits<ScalarValueType>::OneValue());
this->SetCurvatureWeight(NumericTraits<ScalarValueType>::OneValue());
}
~ShapeDetectionLevelSetFunction() override = default;
};
} // end namespace itk
#ifndef ITK_MANUAL_INSTANTIATION
# include "itkShapeDetectionLevelSetFunction.hxx"
#endif
#endif
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