ITK  5.2.0
Insight Toolkit
Examples/Filtering/RGBCurvatureAnisotropicDiffusionImageFilter.cxx
/*=========================================================================
*
* 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
*
* http://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.
*
*=========================================================================*/
// Software Guide : BeginCommandLineArgs
// INPUTS: {VisibleWomanHeadSlice.png}
// OUTPUTS: {RGBCurvatureAnisotropicDiffusionImageFilterOutput.png}
// ARGUMENTS: 20 0.125
// Software Guide : EndCommandLineArgs
// Software Guide : BeginLatex
//
// The vector anisotropic diffusion approach can be applied equally well to
// color images. As in the vector case, each RGB component is diffused
// independently. The following example illustrates the use of the
// \doxygen{VectorCurvatureAnisotropicDiffusionImageFilter} on an image with
// \doxygen{RGBPixel} type.
//
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!RGB
// Images}
//
// Software Guide : EndLatex
// Software Guide : BeginLatex
//
// The first step required to use this filter is to include its header file.
//
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!header}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Also the headers for \code{Image} and \code{RGBPixel} type are required.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkRGBPixel.h"
#include "itkImage.h"
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// It is desirable to perform the computation on the RGB image using
// \code{float} representation. However for input and output purposes
// \code{unsigned char} RGB components are commonly used. It is necessary to
// cast the type of color components in the pipeline before writing them to
// a file. The \doxygen{CastImageFilter} is used to achieve this goal.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
int
main(int argc, char * argv[])
{
if (argc < 5)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputRGBImageFile outputRGBImageFile ";
std::cerr << "numberOfIterations timeStep " << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// The image type is defined using the pixel type and the dimension.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using InputPixelType = itk::RGBPixel<float>;
using InputImageType = itk::Image<InputPixelType, 2>;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The filter type is now instantiated and a filter object is created by
// the \code{New()} method.
//
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!instantiation}
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!New()}
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!Pointer}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using FilterType =
InputImageType>;
FilterType::Pointer filter = FilterType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The input image can be obtained from the output of another
// filter. Here, an image reader is used as a source.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
ReaderType::Pointer reader = ReaderType::New();
reader->SetFileName(argv[1]);
filter->SetInput(reader->GetOutput());
// Software Guide : EndCodeSnippet
const unsigned int numberOfIterations = std::stoi(argv[3]);
const double timeStep = std::stod(argv[4]);
// Software Guide : BeginLatex
//
// This filter requires two parameters: the number of iterations to be
// performed and the time step used in the computation of the level set
// evolution. These parameters are set using the methods
// \code{SetNumberOfIterations()} and \code{SetTimeStep()} respectively.
// The filter can be executed by invoking \code{Update()}.
//
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!Update()}
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!SetTimeStep()}
// \index{itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter!SetNumberOfIterations()}
// \index{SetTimeStep()!itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter}
// \index{SetNumberOfIterations()!itk::Vector\-Curvature\-Anisotropic\-Diffusion\-Image\-Filter}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
filter->SetNumberOfIterations(numberOfIterations);
filter->SetTimeStep(timeStep);
filter->SetConductanceParameter(1.0);
filter->Update();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The filter output is now cast to \code{unsigned char} RGB components by
// using the \doxygen{CastImageFilter}.
//
// \index{itk::CastImageFilter!instantiation}
// \index{itk::CastImageFilter!New()}
// \index{itk::CastImageFilter!Pointer}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using WritePixelType = itk::RGBPixel<unsigned char>;
using WriteImageType = itk::Image<WritePixelType, 2>;
CasterType::Pointer caster = CasterType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Finally, the writer type can be instantiated. One writer is created and
// connected to the output of the cast filter.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
WriterType::Pointer writer = WriterType::New();
caster->SetInput(filter->GetOutput());
writer->SetInput(caster->GetOutput());
writer->SetFileName(argv[2]);
writer->Update();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// \begin{figure} \center
// \includegraphics[width=0.44\textwidth]{VisibleWomanHeadSlice}
// \includegraphics[width=0.44\textwidth]{RGBCurvatureAnisotropicDiffusionImageFilterOutput}
// \itkcaption[VectorCurvatureAnisotropicDiffusionImageFilter output on RGB]
// {Effect of the VectorCurvatureAnisotropicDiffusionImageFilter on a RGB
// image from a cryogenic section of the Visible Woman data set.}
// \label{fig:RGBVectorCurvatureAnisotropicDiffusionImageFilterInputOutput}
// \end{figure}
//
// Figure
// \ref{fig:RGBVectorCurvatureAnisotropicDiffusionImageFilterInputOutput}
// illustrates the effect of this filter on a RGB image from a cryogenic
// section of the Visible Woman data set. In this example the filter was
// run with a time step of $0.125$, and $20$ iterations. The input image
// has $570 \times 670$ pixels and the processing took $4$ minutes on a
// Pentium 4 at 2GHz.
//
// Software Guide : EndLatex
// Software Guide : BeginLatex
//
// \begin{figure} \center
// \includegraphics[width=0.32\textwidth]{VisibleWomanEyeSlice}
// \includegraphics[width=0.32\textwidth]{RGBGradientAnisotropicDiffusionImageFilterOutput2}
// \includegraphics[width=0.32\textwidth]{RGBCurvatureAnisotropicDiffusionImageFilterOutput2}
// \itkcaption[Various Anisotropic Diffusion compared] {Comparison between
// the gradient (center) and curvature (right) Anisotropic Diffusion
// filters. Original image at left.}
// \label{fig:ComparisionGradientCurvatureRGBAnisotropicDiffusion}
// \end{figure}
//
// Figure \ref{fig:ComparisionGradientCurvatureRGBAnisotropicDiffusion}
// compares the effect of the gradient and curvature anisotropic diffusion
// filters on a small region of the same cryogenic slice used in Figure
// \ref{fig:RGBVectorCurvatureAnisotropicDiffusionImageFilterInputOutput}.
// The region used in this figure is only $127 \times 162$ pixels and took
// $14$ seconds to compute on the same platform.
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}
itk::CastImageFilter
Casts input pixels to output pixel type.
Definition: itkCastImageFilter.h:104
itkVectorCurvatureAnisotropicDiffusionImageFilter.h
itk::RGBPixel
Represent Red, Green and Blue components for color images.
Definition: itkRGBPixel.h:58
itkRGBPixel.h
itkImageFileReader.h
itkImage.h
itkCastImageFilter.h
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::ImageFileWriter
Writes image data to a single file.
Definition: itkImageFileWriter.h:87
itk::VectorCurvatureAnisotropicDiffusionImageFilter
Definition: itkVectorCurvatureAnisotropicDiffusionImageFilter.h:68
itkImageFileWriter.h
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86