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/*
* Copyright (C) 2005-2017 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.
*/
// Software Guide : BeginCommandLineArgs
// INPUTS: {QB_Toulouse_Ortho_PAN.tif}
// OUTPUTS: {QB_Toulouse_Ortho_PAN_rescaled.png}, {QB_Toulouse_Ortho_PAN_casted.png}
// Software Guide : EndCommandLineArgs
// Software Guide : BeginLatex
//
// On one hand, satellite images are commonly coded on more than 8 bits to provide
// the dynamic range required from shadows to clouds. On the other hand, image formats
// in use for printing and display are usually limited to 8 bits. We need to convert the value
// to enable a proper display. This is usually done using linear scaling. Of course, you have
// to be aware that some information is lost in the process.
//
// Software Guide : EndLatex
#include "otbImage.h"
#include "otbImageFileReader.h"
#include "otbImageFileWriter.h"
#include "itkUnaryFunctorImageFilter.h"
#include "itkRescaleIntensityImageFilter.h"
#include "itkCastImageFilter.h"
int main(int argc, char * argv[])
{
if (argc != 4)
{
std::cerr << "Usage: " << argv[0] << " <inputImageFile> ";
std::cerr << " <outputRescaledImageFile> <outputCastedImageFile>" <<
std::endl;
return EXIT_FAILURE;
}
typedef unsigned short InputPixelType;
typedef unsigned char OutputPixelType;
typedef otb::Image<InputPixelType, 2> InputImageType;
typedef otb::Image<OutputPixelType, 2> OutputImageType;
typedef otb::ImageFileReader<InputImageType> ReaderType;
ReaderType::Pointer reader = ReaderType::New();
reader->SetFileName(argv[1]);
// Software Guide : BeginLatex
//
// The \doxygen{itk}{RescaleIntensityImageFilter} is used to rescale the value:
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
typedef itk::RescaleIntensityImageFilter<InputImageType,
OutputImageType> RescalerType;
RescalerType::Pointer rescaler = RescalerType::New();
rescaler->SetInput(reader->GetOutput());
// Software Guide : EndCodeSnippet
typedef otb::ImageFileWriter<OutputImageType> WriterType;
WriterType::Pointer writer = WriterType::New();
writer->SetFileName(argv[2]);
writer->SetInput(rescaler->GetOutput());
writer->Update();
typedef itk::CastImageFilter<InputImageType, OutputImageType> CasterType;
CasterType::Pointer caster = CasterType::New();
caster->SetInput(reader->GetOutput());
writer->SetFileName(argv[3]);
writer->SetInput(caster->GetOutput());
writer->Update();
// Software Guide : BeginLatex
// Figure~\ref{fig:SCALING_FILTER} illustrates the difference between a proper scaling and
// a simple truncation of the value and demonstrates why it is
// important to keep this in mind.
// \begin{figure}
// \center
// \includegraphics[width=0.44\textwidth]{QB_Toulouse_Ortho_PAN_casted.eps}
// \includegraphics[width=0.44\textwidth]{QB_Toulouse_Ortho_PAN_rescaled.eps}
// \itkcaption[Scaling images]{On the left, the image obtained by truncated pixel values
// at the dynamic acceptable for a png file (between 0 and 255). On the right,
// the same image with
// a proper rescaling}
// \label{fig:SCALING_FILTER}
// \end{figure}
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}
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