ITK  5.2.0
Insight Toolkit
Examples/IO/ImageReadRegionOfInterestWrite.cxx
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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
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* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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*=========================================================================*/
// Software Guide : BeginLatex
//
// This example should arguably be placed in the previous filtering
// chapter. However its usefulness for typical IO operations makes it
// interesting to mention here. The purpose of this example is to read an
// image, extract a subregion and write this subregion to a file. This is a
// common task when we want to apply a computationally intensive method to
// the region of interest of an image.
//
// As usual with ITK IO, we begin by including the appropriate header files.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The \doxygen{RegionOfInterestImageFilter} is the filter used to extract a
// region from an image. Its header is included below.
//
// \index{itk::RegionOfInterestImageFilter!header}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
#include "itkImage.h"
int
main(int argc, char ** argv)
{
// Verify the number of parameters in the command line
if (argc < 7)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile " << std::endl;
std::cerr << " startX startY sizeX sizeY" << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// Image types are defined below.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using InputPixelType = signed short;
using OutputPixelType = signed short;
constexpr unsigned int Dimension = 2;
using InputImageType = itk::Image<InputPixelType, Dimension>;
using OutputImageType = itk::Image<OutputPixelType, Dimension>;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The types for the \doxygen{ImageFileReader} and
// \doxygen{ImageFileWriter} are instantiated using the image types.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The RegionOfInterestImageFilter type is instantiated using
// the input and output image types. A filter object is created with the
// \code{New()} method and assigned to a \doxygen{SmartPointer}.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using FilterType =
FilterType::Pointer filter = FilterType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The RegionOfInterestImageFilter requires a region to be
// defined by the user. The region is specified by an \doxygen{Index}
// indicating the pixel where the region starts and an \doxygen{Size}
// indicating how many pixels the region has along each dimension. In this
// example, the specification of the region is taken from the command line
// arguments (this example assumes that a 2D image is being processed).
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
start[0] = std::stoi(argv[3]);
start[1] = std::stoi(argv[4]);
// Software Guide : EndCodeSnippet
// Software Guide : BeginCodeSnippet
size[0] = std::stoi(argv[5]);
size[1] = std::stoi(argv[6]);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// An \doxygen{ImageRegion} object is created and initialized with start
// and size obtained from the command line.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
desiredRegion.SetSize(size);
desiredRegion.SetIndex(start);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Then the region is passed to the filter using the
// \code{SetRegionOfInterest()} method.
//
// \index{itk::RegionOfInterestImageFilter!SetRegionOfInterest()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
filter->SetRegionOfInterest(desiredRegion);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Below, we create the reader and writer using the \code{New()} method and
// assign the result to a \doxygen{SmartPointer}.
//
// \index{itk::ImageFileReader!New()}
// \index{itk::ImageFileWriter!New()}
// \index{itk::ImageFileReader!SmartPointer}
// \index{itk::ImageFileWriter!SmartPointer}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
// Software Guide : EndCodeSnippet
//
// Here we recover the file names from the command line arguments
//
const char * inputFilename = argv[1];
const char * outputFilename = argv[2];
// Software Guide : BeginLatex
//
// The name of the file to be read or written is passed with the
// \code{SetFileName()} method.
//
// \index{itk::ImageFileReader!SetFileName()}
// \index{itk::ImageFileWriter!SetFileName()}
// \index{SetFileName()!itk::ImageFileReader}
// \index{SetFileName()!itk::ImageFileWriter}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
reader->SetFileName(inputFilename);
writer->SetFileName(outputFilename);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Below we connect the reader, filter and writer to form the data
// processing pipeline.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
filter->SetInput(reader->GetOutput());
writer->SetInput(filter->GetOutput());
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Finally we execute the pipeline by invoking \code{Update()} on the
// writer. The call is placed in a \code{try/catch} block in case
// exceptions are thrown.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
try
{
writer->Update();
}
catch (const itk::ExceptionObject & err)
{
std::cerr << "ExceptionObject caught !" << std::endl;
std::cerr << err << std::endl;
return EXIT_FAILURE;
}
// Software Guide : EndCodeSnippet
return EXIT_SUCCESS;
}
itkImageFileReader.h
itk::GTest::TypedefsAndConstructors::Dimension2::SizeType
ImageBaseType::SizeType SizeType
Definition: itkGTestTypedefsAndConstructors.h:49
itkImage.h
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::GTest::TypedefsAndConstructors::Dimension2::IndexType
ImageBaseType::IndexType IndexType
Definition: itkGTestTypedefsAndConstructors.h:50
itk::ImageFileWriter
Writes image data to a single file.
Definition: itkImageFileWriter.h:87
itk::GTest::TypedefsAndConstructors::Dimension2::RegionType
ImageBaseType::RegionType RegionType
Definition: itkGTestTypedefsAndConstructors.h:54
itkImageFileWriter.h
itkRegionOfInterestImageFilter.h
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86
itk::ImageRegion::SetSize
void SetSize(const SizeType &size)
Definition: itkImageRegion.h:174
itk::RegionOfInterestImageFilter
Extract a region of interest from the input image.
Definition: itkRegionOfInterestImageFilter.h:54
itk::GTest::TypedefsAndConstructors::Dimension2::Dimension
constexpr unsigned int Dimension
Definition: itkGTestTypedefsAndConstructors.h:44