ITK  5.2.0
Insight Toolkit
Examples/Iterators/ShapedNeighborhoodIterators2.cxx
/*=========================================================================
*
* 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
*
* http://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.
*
*=========================================================================*/
// SoftwareGuide : BeginCommandLineArgs
// INPUTS: {BinaryImage.png}
// OUTPUTS: {ShapedNeighborhoodIterators1b.png}
// ARGUMENTS: 4
// SoftwareGuide : EndCommandLineArgs
#include <cmath>
int
main(int argc, char ** argv)
{
if (argc < 4)
{
std::cerr << "Missing parameters. " << std::endl;
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImageFile outputImageFile element_radius"
<< std::endl;
return EXIT_FAILURE;
}
using PixelType = unsigned char;
using ImageType = itk::Image<PixelType, 2>;
using ReaderType = itk::ImageFileReader<ImageType>;
using ShapedNeighborhoodIteratorType =
ReaderType::Pointer reader = ReaderType::New();
reader->SetFileName(argv[1]);
unsigned int element_radius = ::std::stoi(argv[3]);
try
{
reader->Update();
}
catch (const itk::ExceptionObject & err)
{
std::cerr << "ExceptionObject caught !" << std::endl;
std::cerr << err << std::endl;
return EXIT_FAILURE;
}
ImageType::Pointer output = ImageType::New();
output->SetRegions(reader->GetOutput()->GetRequestedRegion());
output->Allocate();
using FaceCalculatorType =
FaceCalculatorType faceCalculator;
FaceCalculatorType::FaceListType faceList;
FaceCalculatorType::FaceListType::iterator fit;
ShapedNeighborhoodIteratorType::RadiusType radius;
radius.Fill(element_radius);
faceList =
faceCalculator(reader->GetOutput(), output->GetRequestedRegion(), radius);
IteratorType out;
const auto rad = static_cast<float>(element_radius);
constexpr PixelType background_value = 0;
constexpr PixelType foreground_value = 255;
for (fit = faceList.begin(); fit != faceList.end(); ++fit)
{
ShapedNeighborhoodIteratorType it(radius, reader->GetOutput(), *fit);
out = IteratorType(output, *fit);
// Creates a circular structuring element by activating all the pixels
// less than radius distance from the center of the neighborhood.
for (float y = -rad; y <= rad; y++)
{
for (float x = -rad; x <= rad; x++)
{
ShapedNeighborhoodIteratorType::OffsetType off;
float dis = std::sqrt(x * x + y * y);
if (dis <= rad)
{
off[0] = static_cast<int>(x);
off[1] = static_cast<int>(y);
it.ActivateOffset(off);
}
}
}
// Software Guide : BeginLatex
//
// The logic of the inner loop can be rewritten to perform
// dilation. Dilation of the set $I$ by $E$ is the set of all $x$ such
// that $E$ positioned at $x$ contains at least one element in $I$.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Implements dilation
for (it.GoToBegin(), out.GoToBegin(); !it.IsAtEnd(); ++it, ++out)
{
ShapedNeighborhoodIteratorType::ConstIterator ci;
bool flag = false;
for (ci = it.Begin(); ci != it.End(); ci++)
{
if (ci.Get() != background_value)
{
flag = true;
break;
}
}
if (flag == true)
{
out.Set(foreground_value);
}
else
{
out.Set(background_value);
}
}
}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The output image is written and visualized directly as a binary image of
// \code{unsigned chars}. Figure~\ref{fig:ShapedNeighborhoodExample2}
// illustrates some results of erosion and dilation on the image
// \code{Examples/Data/BinaryImage.png}. Applying erosion and dilation
// in sequence effects the morphological operations of opening and closing.
//
// \begin{figure} \centering
// \includegraphics[width=0.18\textwidth]{BinaryImage}
// \includegraphics[width=0.18\textwidth]{ShapedNeighborhoodIterators1a}
// \includegraphics[width=0.18\textwidth]{ShapedNeighborhoodIterators1b}
// \includegraphics[width=0.18\textwidth]{ShapedNeighborhoodIterators1c}
// \includegraphics[width=0.18\textwidth]{ShapedNeighborhoodIterators1d}
// \itkcaption[Binary image morphology]{The effects of morphological
// operations on a binary image using a circular structuring element of
// size 4. From left to right are the original image, erosion, dilation,
// opening, and closing. The opening operation is erosion of the image
// followed by dilation. Closing is dilation of the image followed by
// erosion.} \protect\label{fig:ShapedNeighborhoodExample2} \end{figure}
//
// Software Guide : EndLatex
using WriterType = itk::ImageFileWriter<ImageType>;
WriterType::Pointer writer = WriterType::New();
writer->SetFileName(argv[2]);
writer->SetInput(output);
try
{
writer->Update();
}
catch (const itk::ExceptionObject & err)
{
std::cerr << "ExceptionObject caught !" << std::endl;
std::cerr << err << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
itk::NeighborhoodAlgorithm::ImageBoundaryFacesCalculator
Splits an image into a main region and several "face" regions which are used to handle computations o...
Definition: itkNeighborhoodAlgorithm.h:63
itkConstShapedNeighborhoodIterator.h
itkNeighborhoodAlgorithm.h
itkImageFileReader.h
itkImageRegionIterator.h
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::ImageRegionIterator
A multi-dimensional iterator templated over image type that walks a region of pixels.
Definition: itkImageRegionIterator.h:80
itk::ImageFileWriter
Writes image data to a single file.
Definition: itkImageFileWriter.h:87
itk::ConstShapedNeighborhoodIterator
Const version of ShapedNeighborhoodIterator, defining iteration of a local N-dimensional neighborhood...
Definition: itkConstShapedNeighborhoodIterator.h:72
itkImageFileWriter.h
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:86