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/*
* Copyright (C) 1999-2011 Insight Software Consortium
* Copyright (C) 2005-2020 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.
*/
// This example should arguably be placed in the filtering
// chapter. However its usefulness for typical IO operations makes it
// interesting to mention here. The purpose of this example is to read and
// image, extract a subregion and write this subregion to a file. This is a
// common task when we want to apply a computationally intensive method to
// the region of interest of an image.
//
// As usual with OTB IO, we begin by including the appropriate header files.
#include "otbImageFileReader.h"
#include "otbImageFileWriter.h"
// The \doxygen{otb}{ExtractROI} is the filter used to extract a
// region from an image. Its header is included below.
//
// \index{otb::ExtractROI!header}
#include "otbExtractROI.h"
int main(int argc, char* argv[])
{
// Verify the number of parameters in the command line
if (argc < 7)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile " << std::endl;
std::cerr << " startX startY sizeX sizeY" << std::endl;
return EXIT_FAILURE;
}
// Image types are defined below.
using InputPixelType = unsigned char;
using OutputPixelType = unsigned char;
const unsigned int Dimension = 2;
using InputImageType = otb::Image<InputPixelType, Dimension>;
using OutputImageType = otb::Image<OutputPixelType, Dimension>;
// The types for the \doxygen{otb}{ImageFileReader} and \doxygen{otb}{ImageFileWriter}
// are instantiated using the image types.
using ReaderType = otb::ImageFileReader<InputImageType>;
using WriterType = otb::ImageFileWriter<OutputImageType>;
// The ExtractROI type is instantiated using
// the input and output pixel types. Using the pixel types as
// template parameters instead of the image types allows
// restricting the use of this class to \doxygen{otb}{Image}s which
// are used with scalar pixel types. See section
// \ref{sec:ExtractROI} for the extraction of ROIs on
// \doxygen{otb}{VectorImage}s. A filter object is created with the
// New() method and assigned to a \doxygen{itk}{SmartPointer}.
using FilterType = otb::ExtractROI<InputImageType::PixelType, OutputImageType::PixelType>;
FilterType::Pointer filter = FilterType::New();
// The ExtractROI requires a region to be
// defined by the user. This is done by defining a rectangle with
// the following methods (the filter assumes that a 2D image is
// being processed, for N-D region extraction, you can use the
// \doxygen{itk}{RegionOfInterestImageFilter} class).
filter->SetStartX(atoi(argv[3]));
filter->SetStartY(atoi(argv[4]));
filter->SetSizeX(atoi(argv[5]));
filter->SetSizeY(atoi(argv[6]));
// Below, we create the reader and writer using the New() method and
// assigning the result to a SmartPointer.
//
// \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();
//
// 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 file to be read or written is 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);
// Below we connect the reader, filter and writer to form the data
// processing pipeline.
filter->SetInput(reader->GetOutput());
writer->SetInput(filter->GetOutput());
// Finally we execute the pipeline by invoking Update() on the writer. The
// call is placed in a \code{try/catch} block in case exceptions are
// thrown.
try
{
writer->Update();
}
catch (itk::ExceptionObject& err)
{
std::cerr << "ExceptionObject caught !" << std::endl;
std::cerr << err << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
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