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/*
* 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.
*/
/* Example usage:
./RatioLineDetectorExample Input/amst2.png Output/amstLineRatios.png Output/amstLineRatioDirections.png 5 1
*/
// This example illustrates the use of the \doxygen{otb}{RatioLineDetectorImageFilter}.
// This filter is used for line detection in SAR images. Its principle
// is described in \cite{tup-98}: a line is detected if two parallel
// edges are present in the images. These edges are detected with the
// ratio of means detector.
//
// The first step required to use this filter is to include its header file.
#include "otbLineRatioDetectorImageFilter.h"
#include "otbImage.h"
#include "otbImageFileReader.h"
#include "itkUnaryFunctorImageFilter.h"
#include "itkRescaleIntensityImageFilter.h"
#include "otbImageFileWriter.h"
int main(int argc, char* argv[])
{
if (argc != 6)
{
std::cerr << "Usage: " << argv[0] << " inputImageFile ";
std::cerr << " outputEdgesImageFile outputDirectionsImageFile length width" << std::endl;
return EXIT_FAILURE;
}
// Then we must decide what pixel type to use for the image. We
// choose to make all computations with floating point precision
// and rescale the results between 0 and 255 in order to export PNG images.
using InternalPixelType = float;
using OutputPixelType = unsigned char;
// The images are defined using the pixel type and the dimension.
using InternalImageType = otb::Image<InternalPixelType, 2>;
using OutputImageType = otb::Image<OutputPixelType, 2>;
// The filter can be instantiated using the image types defined above.
using FilterType = otb::LineRatioDetectorImageFilter<InternalImageType, InternalImageType>;
// An \doxygen{otb}{ImageFileReader} class is also instantiated in order to read
// image data from a file.
using ReaderType = otb::ImageFileReader<InternalImageType>;
// An \doxygen{otb}{ImageFileWriter} is instantiated in order to write the
// output image to a file.
using WriterType = otb::ImageFileWriter<OutputImageType>;
// The intensity rescaling of the results will be carried out by the
// \code{itk::RescaleIntensityImageFilter} which is templated by the
// input and output image types.
using RescalerType = itk::RescaleIntensityImageFilter<InternalImageType, OutputImageType>;
// Both the filter and the reader are created by invoking their \code{New()}
// methods and assigning the result to SmartPointers.
ReaderType::Pointer reader = ReaderType::New();
FilterType::Pointer filter = FilterType::New();
// The same is done for the rescaler and the writer.
RescalerType::Pointer rescaler = RescalerType::New();
WriterType::Pointer writer = WriterType::New();
reader->SetFileName(argv[1]);
// The \code{itk::RescaleIntensityImageFilter} needs to know which
// is the minimu and maximum values of the output generated
// image. Those can be chosen in a generic way by using the
// \code{NumericTraits} functions, since they are templated over
// the pixel type.
rescaler->SetOutputMinimum(itk::NumericTraits<OutputPixelType>::min());
rescaler->SetOutputMaximum(itk::NumericTraits<OutputPixelType>::max());
// The image obtained with the reader is passed as input to the
// \doxygen{otb}{LineRatioDetectorImageFilter}. The pipeline is built as follows.
//
// \index{otb::LineRatioDetectorImageFilter!SetInput()}
filter->SetInput(reader->GetOutput());
rescaler->SetInput(filter->GetOutput());
writer->SetInput(rescaler->GetOutput());
// The methods \code{SetLengthLine()} and \code{SetWidthLine()}
// allow setting the minimum length and the typical width of the
// lines which are to be detected.
//
// \index{otb::LineRatioDetector!SetWidthLine()}
// \index{otb::LineRatioDetector!SetLengthLine()}
filter->SetLengthLine(atoi(argv[4]));
filter->SetWidthLine(atoi(argv[5]));
// The filter is executed by invoking the \code{Update()} method. If the
// filter is part of a larger image processing pipeline, calling
// \code{Update()} on a downstream filter will also trigger update of this
// filter.
filter->Update();
writer->SetFileName(argv[2]);
writer->Update();
// We can also obtain the direction of the lines by invoking the
// \code{GetOutputDirection()} method.
writer->SetFileName(argv[3]);
rescaler->SetInput(filter->GetOutputDirection());
writer->SetInput(rescaler->GetOutput());
writer->Update();
// Figure~\ref{fig:LINERATIO_FILTER}
// shows the result of applying the LineRatio edge detector filter
// to a SAR image. \begin{figure} \center
// \includegraphics[width=0.25\textwidth]{amst.eps}
// \includegraphics[width=0.25\textwidth]{amstLineRatios.eps}
// \includegraphics[width=0.25\textwidth]{amstLineRatioDirections.eps}
// \itkcaption[Line Ratio Detector Application]{Result of applying
// the \doxygen{otb}{LineRatioDetectorImageFilter} to a SAR
// image. From left to right : original image, line intensity and
// edge orientation.} \label{fig:LINERATIO_FILTER} \end{figure}
//
// \relatedClasses
// \begin{itemize}
// \item \doxygen{otb}{LineCorrelationDetectorImageFilter}
// \end{itemize}
return EXIT_SUCCESS;
}
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