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/*=========================================================================
*
* Copyright Insight Software Consortium
*
* 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: {BrainProtonDensitySlice.png}
// ARGUMENTS: {DerivativeImageFilterFloatOutput.mhd}
// OUTPUTS: {DerivativeImageFilterOutput.png}
// ARGUMENTS: 1 0
// Software Guide : EndCommandLineArgs
// Software Guide : BeginLatex
//
// The \doxygen{DerivativeImageFilter} is used for computing the partial
// derivative of an image, the derivative of an image along a particular axial
// direction.
//
// \index{itk::DerivativeImageFilter}
//
// Software Guide : EndLatex
#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkRescaleIntensityImageFilter.h"
// Software Guide : BeginLatex
//
// The header file corresponding to this filter should be included first.
//
// \index{itk::DerivativeImageFilter!header}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkDerivativeImageFilter.h"
// Software Guide : EndCodeSnippet
int main( int argc, char * argv[] )
{
if( argc < 6 )
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile normalizedOutputImageFile ";
std::cerr << " derivativeOrder direction" << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// Next, the pixel types for the input and output images must be defined and, with
// them, the image types can be instantiated. Note that it is important to
// select a signed type for the image, since the values of the derivatives
// will be positive as well as negative.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
typedef float InputPixelType;
typedef float OutputPixelType;
const unsigned int Dimension = 2;
typedef itk::Image< InputPixelType, Dimension > InputImageType;
typedef itk::Image< OutputPixelType, Dimension > OutputImageType;
// Software Guide : EndCodeSnippet
typedef itk::ImageFileReader< InputImageType > ReaderType;
typedef itk::ImageFileWriter< OutputImageType > WriterType;
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
reader->SetFileName( argv[1] );
writer->SetFileName( argv[2] );
// Software Guide : BeginLatex
//
// Using the image types, it is now possible to define the filter type
// and create the filter object.
//
// \index{itk::DerivativeImageFilter!instantiation}
// \index{itk::DerivativeImageFilter!New()}
// \index{itk::DerivativeImageFilter!Pointer}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
typedef itk::DerivativeImageFilter<
InputImageType, OutputImageType > FilterType;
FilterType::Pointer filter = FilterType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The order of the derivative is selected with the \code{SetOrder()}
// method. The direction along which the derivative will be computed is
// selected with the \code{SetDirection()} method.
//
// \index{itk::DerivativeImageFilter!SetOrder()}
// \index{itk::DerivativeImageFilter!SetDirection()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
filter->SetOrder( atoi( argv[4] ) );
filter->SetDirection( atoi( argv[5] ) );
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The input to the filter can be taken from any other filter, for example
// a reader. The output can be passed down the pipeline to other filters,
// for example, a writer. An \code{Update()} call on any downstream filter will
// trigger the execution of the derivative filter.
//
// \index{itk::DerivativeImageFilter!SetInput()}
// \index{itk::DerivativeImageFilter!GetOutput()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
filter->SetInput( reader->GetOutput() );
writer->SetInput( filter->GetOutput() );
writer->Update();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// \begin{figure}
// \center
// \includegraphics[width=0.44\textwidth]{BrainProtonDensitySlice}
// \includegraphics[width=0.44\textwidth]{DerivativeImageFilterOutput}
// \itkcaption[Effect of the Derivative filter.]{Effect of the Derivative filter
// on a slice from a MRI proton density brain image.}
// \label{fig:DerivativeImageFilterOutput}
// \end{figure}
//
// Figure \ref{fig:DerivativeImageFilterOutput} illustrates the effect of
// the DerivativeImageFilter on a slice of MRI brain image. The derivative
// is taken along the $x$ direction. The sensitivity to noise in the image
// is evident from this result.
//
// Software Guide : EndLatex
typedef itk::Image< unsigned char, Dimension > WriteImageType;
typedef itk::RescaleIntensityImageFilter<
OutputImageType,
WriteImageType > NormalizeFilterType;
typedef itk::ImageFileWriter< WriteImageType > NormalizedWriterType;
NormalizeFilterType::Pointer normalizer = NormalizeFilterType::New();
NormalizedWriterType::Pointer normalizedWriter = NormalizedWriterType::New();
normalizer->SetInput( filter->GetOutput() );
normalizedWriter->SetInput( normalizer->GetOutput() );
normalizer->SetOutputMinimum( 0 );
normalizer->SetOutputMaximum( 255 );
normalizedWriter->SetFileName( argv[3] );
normalizedWriter->Update();
return EXIT_SUCCESS;
}
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