ImageReadCastWrite.cxxΒΆ
Example source code (ImageReadCastWrite.cxx):
/*
* Copyright (C) 1999-2011 Insight Software Consortium
* Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
*
* This file is part of Orfeo Toolbox
*
* https://www.orfeo-toolbox.org/
*
* 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
*
* 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.
*/
// Given that \href{http://www.itk.org}{ITK} and OTB are based on the Generic
// Programming paradigm, most of the types are defined at compilation
// time. It is sometimes important to anticipate conversion between different
// types of images. The following example illustrates the common case of
// reading an image of one pixel type and writing it on a different pixel
// type. This process not only involves casting but also rescaling the image
// intensity since the dynamic range of the input and output pixel types can
// be quite different. The \doxygen{itk}{RescaleIntensityImageFilter} is used
// here to linearly rescale the image values.
//
// The first step in this example is to include the appropriate headers.
//
// \index{otb::ImageFileReader!header}
// \index{otb::ImageFileWriter!header}
// \index{itk::RescaleIntensityImageFilter!header}
#include "otbImageFileReader.h"
#include "otbImageFileWriter.h"
#include "itkUnaryFunctorImageFilter.h"
#include "itkRescaleIntensityImageFilter.h"
#include "otbImage.h"
int main(int argc, char* argv[])
{
// Verify the number of parameters in the command line
if (argc < 3)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile " << std::endl;
return EXIT_FAILURE;
}
// Then, as usual, a decision should be made about the pixel type that
// should be used to represent the images. Note that when reading an
// image, this pixel type \textbf{is not necessarily} the pixel type of
// the image stored in the file. Instead, it is the type that will be
// used to store the image as soon as it is read into memory.
using InputPixelType = float;
using OutputPixelType = unsigned char;
const unsigned int Dimension = 2;
using InputImageType = otb::Image<InputPixelType, Dimension>;
using OutputImageType = otb::Image<OutputPixelType, Dimension>;
// We can now instantiate the types of the reader and writer. These two
// classes are parameterized over the image type.
//
// \index{otb::ImageFileReader!Instantiation}
// \index{otb::ImageFileWriter!Instantiation}
using ReaderType = otb::ImageFileReader<InputImageType>;
using WriterType = otb::ImageFileWriter<OutputImageType>;
// Below we instantiate the RescaleIntensityImageFilter class that will
// linearly scale the image intensities.
using FilterType = itk::RescaleIntensityImageFilter<InputImageType, OutputImageType>;
// A filter object is constructed and the minimum and maximum values of
// the output are selected using the SetOutputMinimum() and
// SetOutputMaximum() methods.
//
// \index{itk::RescaleIntensityImageFilter!SetOutputMinimum()}
// \index{itk::RescaleIntensityImageFilter!SetOutputMaximum()}
FilterType::Pointer filter = FilterType::New();
filter->SetOutputMinimum(0);
filter->SetOutputMaximum(255);
// Then, we create the reader and writer and connect the pipeline.
//
// \index{otb::ImageFileReader!New()}
// \index{otb::ImageFileWriter!New()}
// \index{otb::ImageFileReader!SmartPointer}
// \index{otb::ImageFileWriter!SmartPointer}
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
filter->SetInput(reader->GetOutput());
writer->SetInput(filter->GetOutput());
//
// Here we recover the file names from the command line arguments
//
const char* inputFilename = argv[1];
const char* outputFilename = argv[2];
// The name of the files to be read and written are passed with the
// SetFileName() method.
//
// \index{otb::ImageFileReader!SetFileName()}
// \index{otb::ImageFileWriter!SetFileName()}
// \index{SetFileName()!otb::ImageFileReader}
// \index{SetFileName()!otb::ImageFileWriter}
reader->SetFileName(inputFilename);
writer->SetFileName(outputFilename);
// Finally we trigger the execution of the pipeline with the Update()
// method on the writer. The output image will then be the scaled and cast
// version of the input image.
try
{
writer->Update();
}
catch (itk::ExceptionObject& err)
{
std::cerr << "ExceptionObject caught !" << std::endl;
std::cerr << err << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}