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/*=========================================================================
*
* Copyright NumFOCUS
*
* 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
*
* https://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
//
// We now use the previous example for building the ScaleSpace of a 2D image.
// Since most of the code is the same, we will focus only on the extra lines
// needed for generating the Scale Space.
//
// Software Guide : EndLatex
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkLaplacianRecursiveGaussianImageFilter.h"
#include <cstdio>
#include <iomanip>
int
main(int argc, char * argv[])
{
if (argc < 4)
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0]
<< " inputImageFile outputImageFileBase numberOfSlices"
<< std::endl;
return EXIT_FAILURE;
}
using InputPixelType = float;
using OutputPixelType = float;
using InputImageType = itk::Image<InputPixelType, 2>;
using OutputImageType = itk::Image<OutputPixelType, 2>;
using ReaderType = itk::ImageFileReader<InputImageType>;
using FilterType =
itk::LaplacianRecursiveGaussianImageFilter<InputImageType,
OutputImageType>;
auto reader = ReaderType::New();
reader->SetFileName(argv[1]);
auto laplacian = FilterType::New();
laplacian->SetNormalizeAcrossScale(true);
laplacian->SetInput(reader->GetOutput());
using WriterType = itk::ImageFileWriter<OutputImageType>;
auto writer = WriterType::New();
writer->SetInput(laplacian->GetOutput());
// Software Guide : BeginLatex
//
// Interestingly, all comes down to looping over several scales,
// by setting different sigma values and selecting the filename
// of the slice corresponding to that scale value.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
int numberOfSlices = std::stoi(argv[3]);
for (int slice = 0; slice < numberOfSlices; ++slice)
{
std::ostringstream filename;
filename << argv[2] << std::setfill('0') << std::setw(3) << slice
<< ".mhd";
writer->SetFileName(filename.str());
const float sigma = static_cast<float>(slice) / 10.0 + 1.0;
laplacian->SetSigma(sigma);
writer->Update();
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The set of images can now be loaded in a Viewer, such as VolView or
// ParaView, and iso-surfaces can be traced at the zero value. These
// surfaces will correspond to the zero-crossings of the laplacian and
// therefore their stability along Scales will represent the significance
// of these features as edges in the original image.
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}
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