ITK  5.0.0 Insight Segmentation and Registration Toolkit
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// Software Guide : BeginLatex
//
// Probably the most common representation of datasets in clinical
// applications is the one that uses sets of DICOM slices in order to compose
// 3-dimensional images. This is the case for CT, MRI and PET scanners. It is
// very common therefore for image analysts to have to process volumetric
// images stored in a set of DICOM files belonging to a
// common DICOM series.
//
// The following example illustrates how to use ITK functionalities in order
// to read a DICOM series into a volume and then save this volume in another
// file format.
//
// The example begins by including the appropriate headers. In particular we
// will need the \doxygen{GDCMImageIO} object in order to have access to the
// capabilities of the GDCM library for reading DICOM files, and the
// \doxygen{GDCMSeriesFileNames} object for generating the lists of filenames
// identifying the slices of a common volumetric dataset.
//
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkImage.h"
#include "itkGDCMImageIO.h"
// Software Guide : EndCodeSnippet
int main( int argc, char* argv[] )
{
if( argc < 3 )
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " DicomDirectory outputFileName [seriesName]"
<< std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// We define the pixel type and dimension of the image to be read. In this
// particular case, the dimensionality of the image is 3, and we assume a
// \code{signed short} pixel type that is commonly used for X-Rays CT scanners.
//
// The image orientation information contained in the direction cosines
// of the DICOM header are read in and passed correctly down the image processing
// pipeline.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using PixelType = signed short;
constexpr unsigned int Dimension = 3;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We use the image type for instantiating the type of the series reader and
// for constructing one object of its type.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// A GDCMImageIO object is created and connected to the reader. This object is
// the one that is aware of the internal intricacies of the DICOM format.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using ImageIOType = itk::GDCMImageIO;
ImageIOType::Pointer dicomIO = ImageIOType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Now we face one of the main challenges of the process of reading a DICOM
// series: to identify from a given directory the set of filenames
// that belong together to the same volumetric image. Fortunately for us, GDCM
// offers functionalities for solving this problem and we just need to invoke
// those functionalities through an ITK class that encapsulates a communication
// with GDCM classes. This ITK object is the GDCMSeriesFileNames. Conveniently,
// we only need to pass to this class the name of the directory where
// the DICOM slices are stored. This is done with the \code{SetDirectory()}
// method. The GDCMSeriesFileNames object will explore the directory and will
// generate a sequence of filenames for DICOM files for one study/series.
// In this example, we also call the \code{SetUseSeriesDetails(true)} function
// that tells the GDCMSeriesFileNames object to use additional DICOM
// information to distinguish unique volumes within the directory. This is
// useful, for example, if a DICOM device assigns the same SeriesID to
// a scout scan and its 3D volume; by using additional DICOM information
// the scout scan will not be included as part of the 3D volume. Note that
// \code{SetUseSeriesDetails(true)} must be called prior to calling
// \code{SetDirectory()}. By default \code{SetUseSeriesDetails(true)} will use
// the following DICOM tags to sub-refine a set of files into multiple series:
//
// \begin{description}
// \item[0020 0011] Series Number
// \item[0018 0024] Sequence Name
// \item[0018 0050] Slice Thickness
// \item[0028 0010] Rows
// \item[0028 0011] Columns
// \end{description}
//
// If this is not enough for your specific case you can always add some more
// restrictions using the \code{AddSeriesRestriction()} method. In this example we will use
// the DICOM Tag: 0008 0021 DA 1 Series Date, to sub-refine each series. The format
// for passing the argument is a string containing first the group then the element
// of the DICOM tag, separated by a pipe ($|$) sign.
//
//
// \index{itk::GDCMSeriesFileNames!SetDirectory()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using NamesGeneratorType = itk::GDCMSeriesFileNames;
NamesGeneratorType::Pointer nameGenerator = NamesGeneratorType::New();
nameGenerator->SetUseSeriesDetails( true );
nameGenerator->SetDirectory( argv[1] );
// Software Guide : EndCodeSnippet
try
{
std::cout << std::endl << "The directory: " << std::endl;
std::cout << std::endl << argv[1] << std::endl << std::endl;
std::cout << "Contains the following DICOM Series: ";
std::cout << std::endl << std::endl;
// Software Guide : BeginLatex
//
// The GDCMSeriesFileNames object first identifies the list of DICOM series
// present in the given directory. We receive that list in a reference
// to a container of strings and then we can do things like print out all
// the series identifiers that the generator had found. Since the process of
// finding the series identifiers can potentially throw exceptions, it is
// wise to put this code inside a \code{try/catch} block.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using SeriesIdContainer = std::vector< std::string >;
const SeriesIdContainer & seriesUID = nameGenerator->GetSeriesUIDs();
auto seriesItr = seriesUID.begin();
auto seriesEnd = seriesUID.end();
while( seriesItr != seriesEnd )
{
std::cout << seriesItr->c_str() << std::endl;
++seriesItr;
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Given that it is common to find multiple DICOM series in the same directory,
// we must tell the GDCM classes what specific series we want to read. In
// this example we do this by checking first if the user has provided a series
// identifier in the command line arguments. If no series identifier has been
// passed, then we simply use the first series found during the exploration of
// the directory.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
std::string seriesIdentifier;
if( argc > 3 ) // If no optional series identifier
{
seriesIdentifier = argv[3];
}
else
{
seriesIdentifier = seriesUID.begin()->c_str();
}
// Software Guide : EndCodeSnippet
std::cout << std::endl << std::endl;
std::cout << "Now reading series: " << std::endl << std::endl;
std::cout << seriesIdentifier << std::endl;
std::cout << std::endl << std::endl;
// Software Guide : BeginLatex
//
// We pass the series identifier to the name generator and ask for all the
// filenames associated to that series. This list is returned in a container of
// strings by the \code{GetFileNames()} method.
//
// \index{itk::GDCMSeriesFileNames!GetFileNames()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using FileNamesContainer = std::vector< std::string >;
FileNamesContainer fileNames;
fileNames = nameGenerator->GetFileNames( seriesIdentifier );
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
//
// The list of filenames can now be passed to the \doxygen{ImageSeriesReader}
// using the \code{SetFileNames()} method.
//
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Finally we can trigger the reading process by invoking the \code{Update()}
// method in the reader. This call as usual is placed inside a \code{try/catch}
// block.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
try
{
}
{
std::cout << ex << std::endl;
return EXIT_FAILURE;
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// At this point, we have a volumetric image in memory that we can access by
// invoking the \code{GetOutput()} method of the reader.
//
// Software Guide : EndLatex
// Software Guide : BeginLatex
//
// We proceed now to save the volumetric image in another file, as specified by
// the user in the command line arguments of this program. Thanks to the
// ImageIO factory mechanism, only the filename extension is needed to identify
// the file format in this case.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
WriterType::Pointer writer = WriterType::New();
writer->SetFileName( argv[2] );
// Software Guide : EndCodeSnippet
std::cout << "Writing the image as " << std::endl << std::endl;
std::cout << argv[2] << std::endl << std::endl;
// Software Guide : BeginLatex
//
// The process of writing the image is initiated by invoking the
// \code{Update()} method of the writer.
//
// Software Guide : EndLatex
try
{
// Software Guide : BeginCodeSnippet
writer->Update();
// Software Guide : EndCodeSnippet
}
{
std::cout << ex << std::endl;
return EXIT_FAILURE;
}
}
{
std::cout << ex << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// Note that in addition to writing the volumetric image to a file we could
// have used it as the input for any 3D processing pipeline. Keep in mind that
// DICOM is simply a file format and a network protocol. Once the image data
// has been loaded into memory, it behaves as any other volumetric dataset that
// you could have loaded from any other file format.
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}