ITK  5.0.0
Insight Segmentation and Registration Toolkit
Examples/IO/ImageSeriesReadWrite2.cxx
/*=========================================================================
*
* 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 : BeginLatex
//
// This example illustrates how to read a series of 2D slices from independent
// files in order to compose a volume. The class \doxygen{ImageSeriesReader}
// is used for this purpose. This class works in combination with a generator
// of filenames that will provide a list of files to be read. In this
// particular example we use the \doxygen{RegularExpressionSeriesFileNames} class as
// filename generator. This generator uses a regular expression for generating a list
// of filenames. The filenames are then ordered according to sub expression.
//
// Regular expressions are a powerful, compact mechanism for parsing strings.
// Expressions consist of the following metacharacters:
//
// \begin{itemize}
//
// \item \^ Matches at beginning of a line
//
// \item \$ Matches at end of a line
//
// \item \. Matches any single character
//
// \item \[ \] Matches any character(s) inside the brackets
//
// \item \[\^ \] Matches any character(s) not inside the brackets
//
// \item \- Matches any character in range on either side of a dash
//
// \item \* Matches preceding pattern zero or more times
//
// \item \+ Matches preceding pattern one or more times
//
// \item \? Matches preceding pattern zero or once only
//
// \item \(\) Saves a matched expression and uses it in a later match
// \begin{itemize}
//
// Note that more than one of these metacharacters can be used in a single
// regular expression in order to create complex search patterns. For example,
// the pattern \{ [^ab1-9] } says to match any character sequence that
// does not begin with the characters "ab" followed by numbers in the
// series one through nine.
//
//
// In order to use the RegularExpressionSeriesFileNames class we should include
// the following headers as shown.
//
// \index{itk::ImageSeriesReader!header}
// \index{itk::RegularExpressionSeriesFileNames!header}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkImage.h"
#include "itkPNGImageIO.h"
// Software Guide : EndCodeSnippet
int main( int argc, char ** argv )
{
// Verify the number of parameters in the command line
if( argc < 5 )
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << "directory regularExression ";
std::cerr << "sortingExpression outputImageFile " << std::endl;
return EXIT_FAILURE;
}
// Software Guide : BeginLatex
//
// We start by defining the \code{PixelType} and \code{ImageType}.
//
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using PixelType = unsigned char;
constexpr unsigned int Dimension = 3;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The image type is used as a template parameter to instantiate
// the reader and writer.
//
// \index{itk::ImageSeriesReader!Instantiation}
// \index{itk::ImageFileWriter!Instantiation}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
// Software Guide : EndCodeSnippet
std::string directory = argv[1];
std::string regularExpression = argv[2];
const unsigned int subMatch = std::stoi( argv[3] );
std::string outputFilename = argv[4];
// Software Guide : BeginLatex
//
// Then, we declare the filenames generator type and create one instance of it.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using NameGeneratorType = itk::RegularExpressionSeriesFileNames;
NameGeneratorType::Pointer nameGenerator = NameGeneratorType::New();
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The filenames generator requires us to provide a pattern of text for the
// regular expression, the sorting expression, as well as the directory where
// the files are stored.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
nameGenerator->SetRegularExpression( regularExpression );
nameGenerator->SetSubMatch( subMatch );
nameGenerator->SetDirectory( directory );
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The ImageIO object that actually performs the read process is now connected
// to the ImageSeriesReader. This is the safest way of making sure that we use
// an ImageIO object that is appropriate for the type of files that we want to
// read.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
reader->SetImageIO( itk::PNGImageIO::New() );
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The filenames of the input files must be provided to the reader. While the
// writer is instructed to write the same volume dataset in a single file.
//
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
reader->SetFileNames( nameGenerator->GetFileNames() );
writer->SetFileName( outputFilename );
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// We connect the output of the reader to the input of the writer.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
writer->SetInput( reader->GetOutput() );
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Finally, execution of the pipeline can be triggered by invoking the
// Update() method in the writer. This call must be placed in a try/catch
// block since exceptions be potentially be thrown in the process of reading
// or writing the images.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
try
{
writer->Update();
}
catch( itk::ExceptionObject & err )
{
std::cerr << "ExceptionObject caught !" << std::endl;
std::cerr << err << std::endl;
return EXIT_FAILURE;
}
// Software Guide : EndCodeSnippet
return EXIT_SUCCESS;
}