ITK  5.2.0
Insight Toolkit
Examples/DataRepresentation/Image/Image5.cxx
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*
* Copyright NumFOCUS
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* 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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* See the License for the specific language governing permissions and
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// Software Guide : BeginLatex
//
// This example illustrates how to import data into the \doxygen{Image}
// class. This is particularly useful for interfacing with other software
// systems. Many systems use a contiguous block of memory as a buffer
// for image pixel data. The current example assumes this is the case and
// feeds the buffer into an \doxygen{ImportImageFilter}, thereby producing an
// image as output.
//
// Here we create a synthetic image with a centered sphere in
// a locally allocated buffer and pass this block of memory to the
// \code{ImportImageFilter}. This example is set up so that on execution, the
// user must provide the name of an output file as a command-line argument.
//
// \index{itk::ImportImageFilter!Instantiation}
// \index{itk::ImportImageFilter!Header}
//
// First, the header file of the \doxygen{ImportImageFilter} class must be
// included.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkImage.h"
// Software Guide : EndCodeSnippet
int
main(int argc, char * argv[])
{
if (argc < 2)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " outputImageFile" << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// Next, we select the data type used to represent the image pixels. We
// assume that the external block of memory uses the same data type to
// represent the pixels.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using PixelType = unsigned char;
constexpr unsigned int Dimension = 3;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The type of the \code{ImportImageFilter} is instantiated in the
// following line.
//
// \index{itk::ImportImageFilter!Instantiation}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// A filter object created using the \code{New()} method is then
// assigned to a \code{SmartPointer}.
//
// \index{itk::ImportImageFilter!Pointer}
// \index{itk::ImportImageFilter!New()}
//
// Software Guide : EndLatex
//
// Software Guide : BeginCodeSnippet
ImportFilterType::Pointer importFilter = ImportFilterType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// This filter requires the user to specify the size of the image to be
// produced as output. The \code{SetRegion()} method is used to this end.
// The image size should exactly match the number of pixels available in the
// locally allocated buffer.
//
// \index{itk::ImportImageFilter!SetRegion()}
// \index{itk::ImportImageFilter!New()}
// \index{itk::ImportImageFilter!New()}
//
// Software Guide : EndLatex
//
// Software Guide : BeginCodeSnippet
size[0] = 200; // size along X
size[1] = 200; // size along Y
size[2] = 200; // size along Z
start.Fill(0);
region.SetIndex(start);
region.SetSize(size);
importFilter->SetRegion(region);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The origin of the output image is specified with the \code{SetOrigin()}
// method.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
const itk::SpacePrecisionType origin[Dimension] = { 0.0, 0.0, 0.0 };
importFilter->SetOrigin(origin);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The spacing of the image is passed with the \code{SetSpacing()} method.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// spacing isotropic volumes to 1.0
const itk::SpacePrecisionType spacing[Dimension] = { 1.0, 1.0, 1.0 };
importFilter->SetSpacing(spacing);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Next we allocate the memory block containing the pixel data to be
// passed to the \code{ImportImageFilter}. Note that we use exactly the
// same size that was specified with the \code{SetRegion()} method. In a
// practical application, you may get this buffer from some other library
// using a different data structure to represent the images.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
const unsigned int numberOfPixels = size[0] * size[1] * size[2];
auto * localBuffer = new PixelType[numberOfPixels];
// Software Guide : EndCodeSnippet
constexpr double radius = 80.0;
// Software Guide : BeginLatex
//
// Here we fill up the buffer with a binary sphere. We use simple
// \code{for()} loops here, similar to those found in the C or FORTRAN
// programming languages. Note that ITK
// does not use \code{for()} loops in its internal code to access
// pixels. All pixel access tasks are instead performed using an
// \doxygen{ImageIterator} that supports the management of
// n-dimensional images.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
constexpr double radius2 = radius * radius;
PixelType * it = localBuffer;
for (unsigned int z = 0; z < size[2]; z++)
{
const double dz =
static_cast<double>(z) - static_cast<double>(size[2]) / 2.0;
for (unsigned int y = 0; y < size[1]; y++)
{
const double dy =
static_cast<double>(y) - static_cast<double>(size[1]) / 2.0;
for (unsigned int x = 0; x < size[0]; x++)
{
const double dx =
static_cast<double>(x) - static_cast<double>(size[0]) / 2.0;
const double d2 = dx * dx + dy * dy + dz * dz;
*it++ = (d2 < radius2) ? 255 : 0;
}
}
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The buffer is passed to the \code{ImportImageFilter} with the
// \code{SetImportPointer()} method. Note that the last argument of this
// method specifies who will be responsible for deleting the memory block
// once it is no longer in use. A \code{false} value indicates that the
// \code{ImportImageFilter} will not try to delete the buffer when its
// destructor is called. A \code{true} value, on the other hand, will allow
// the filter to delete the memory block upon destruction of the import
// filter.
//
// For the \code{ImportImageFilter} to appropriately delete the
// memory block, the memory must be allocated with the C++
// \code{new()} operator. Memory allocated with other memory
// allocation mechanisms, such as C \code{malloc} or \code{calloc}, will not
// be deleted properly by the \code{ImportImageFilter}. In
// other words, it is the application programmer's responsibility
// to ensure that \code{ImportImageFilter} is only given
// permission to delete the C++ \code{new} operator-allocated memory.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
const bool importImageFilterWillOwnTheBuffer = true;
importFilter->SetImportPointer(
localBuffer, numberOfPixels, importImageFilterWillOwnTheBuffer);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Finally, we can connect the output of this filter to a pipeline.
// For simplicity we just use a writer here, but it could be any other
// filter.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using WriterType = itk::ImageFileWriter<ImageType>;
WriterType::Pointer writer = WriterType::New();
writer->SetFileName(argv[1]);
writer->SetInput(importFilter->GetOutput());
// Software Guide : EndCodeSnippet
try
{
writer->Update();
}
catch (const itk::ExceptionObject & exp)
{
std::cerr << "Exception caught !" << std::endl;
std::cerr << exp << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// Note that we do not call \code{delete} on the buffer since we pass
// \code{true} as the last argument of \code{SetImportPointer()}. Now the
// buffer is owned by the \code{ImportImageFilter}.
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}
itk::GTest::TypedefsAndConstructors::Dimension2::SizeType
ImageBaseType::SizeType SizeType
Definition: itkGTestTypedefsAndConstructors.h:49
itkImage.h
itk::Index::Fill
void Fill(IndexValueType value)
Definition: itkIndex.h:270
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
itk::SpacePrecisionType
double SpacePrecisionType
Definition: itkFloatTypes.h:30
itkImportImageFilter.h
itk::ImportImageFilter
Import data from a standard C array into an itk::Image.
Definition: itkImportImageFilter.h:43
itkImageFileWriter.h
itk::ImageRegion::SetIndex
void SetIndex(const IndexType &index)
Definition: itkImageRegion.h:153
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86
itk::GTest::TypedefsAndConstructors::Dimension2::Dimension
constexpr unsigned int Dimension
Definition: itkGTestTypedefsAndConstructors.h:44