ENH: Migrate example itkGrayscaleFunctionDilateImageFilter

* Migrate the itkGrayscaleFunctionDilateImageFilter.cxx example from
`ITK/Examples/Filtering` to
`ITKSphinxExamples/src/Filtering/MathematicalMorphology/DilateAGrayscaleImage`.

* Add new baseline output image as `OutputBaseline.png`.

* Add an equivalent python implementation of the example.

Author: jadh4v

src/Filtering/MathematicalMorphology/CMakeLists.txt

@@ -32,3 +32,8 @@ add_example(ErodeBinaryImageUsingFlatStruct)
 compare_to_baseline(EXAMPLE_NAME ErodeBinaryImageUsingFlatStruct
         BASELINE_PREFIX ErodeBinaryImageUsingFlatStruct
         )
+
+add_example(DilateUsingFunctionalGrayscale)
+compare_to_baseline(EXAMPLE_NAME DilateUsingFunctionalGrayscale
+        BASELINE_PREFIX OutputBaseline
+        )

src/Filtering/MathematicalMorphology/DilateUsingFunctionalGrayscale/CMakeLists.txt

@@ -0,0 +1,42 @@
+cmake_minimum_required(VERSION 3.16.3)
+
+project( DilateUsingFunctionalGrayscale )
+
+find_package( ITK REQUIRED
+  COMPONENTS
+  ITKCommon
+  ITKIOImageBase
+  ITKMathematicalMorphology
+  ITKIOPNG
+  )
+include( ${ITK_USE_FILE} )
+
+add_executable( DilateUsingFunctionalGrayscale Code.cxx )
+target_link_libraries( DilateUsingFunctionalGrayscale ${ITK_LIBRARIES} )
+
+install( TARGETS DilateUsingFunctionalGrayscale
+  DESTINATION bin/ITKSphinxExamples/Filtering/MathematicalMorphology
+  COMPONENT Runtime
+)
+
+install( FILES Code.cxx CMakeLists.txt
+  DESTINATION share/ITKSphinxExamples/Code/Filtering/MathematicalMorphology/DilateUsingFunctionalGrayscale
+  COMPONENT Code
+)
+
+enable_testing()
+add_test( NAME DilateUsingFunctionalGrayscaleTest
+  COMMAND ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/DilateUsingFunctionalGrayscale
+    ${CMAKE_CURRENT_BINARY_DIR}/cthead1.png
+    Output.png
+    5
+  )
+
+if( ITK_WRAP_PYTHON )
+  add_test( NAME DilateUsingFunctionalGrayscaleTestPython
+    COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/Code.py
+      ${CMAKE_CURRENT_BINARY_DIR}/cthead1.png
+      OutputPython.png
+      5
+    )
+endif()

src/Filtering/MathematicalMorphology/DilateUsingFunctionalGrayscale/Code.cxx

@@ -0,0 +1,79 @@
+/*=========================================================================
+ *
+ *  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.
+ *
+ *=========================================================================*/
+
+#include "itkFlatStructuringElement.h"
+#include "itkGrayscaleFunctionDilateImageFilter.h"
+#include "itkImage.h"
+#include "itkImageFileReader.h"
+#include "itkImageFileWriter.h"
+
+int
+main(int argc, char * argv[])
+{
+  if (argc < 4)
+  {
+    std::cerr << "Usage: " << std::endl;
+    std::cerr << argv[0] << " <inputImage> <outputImage> <radius>";
+    std::cerr << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  constexpr unsigned int Dimension = 2;
+  using PixelType = unsigned char;
+
+  using ImageType = itk::Image<PixelType, Dimension>;
+
+  using ReaderType = itk::ImageFileReader<ImageType>;
+  using WriterType = itk::ImageFileWriter<ImageType>;
+
+  auto reader = ReaderType::New();
+  auto writer = WriterType::New();
+
+  const char *       inputImage = argv[1];
+  const char *       outputImage = argv[2];
+  const unsigned int radiusValue = std::stoi(argv[3]);
+
+  reader->SetFileName(inputImage);
+  writer->SetFileName(outputImage);
+
+  using StructuringElementType = itk::FlatStructuringElement<Dimension>;
+  StructuringElementType::RadiusType radius;
+  radius.Fill(radiusValue);
+  StructuringElementType structuringElement = StructuringElementType::Ball(radius);
+
+  using FilterType = itk::GrayscaleFunctionDilateImageFilter<ImageType, ImageType, StructuringElementType>;
+
+  auto filter = FilterType::New();
+
+  filter->SetKernel(structuringElement);
+
+  filter->SetInput(reader->GetOutput());
+  writer->SetInput(filter->GetOutput());
+
+  try
+  {
+    writer->Update();
+  }
+  catch (const itk::ExceptionObject & excp)
+  {
+    std::cerr << excp << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  return EXIT_SUCCESS;
+}

src/Filtering/MathematicalMorphology/DilateUsingFunctionalGrayscale/Code.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python
+
+# 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.
+
+import itk
+import argparse
+
+itk.auto_progress(2)
+
+parser = argparse.ArgumentParser(
+    description="Dilate an image using functional grayscale morphology."
+)
+parser.add_argument("input_image")
+parser.add_argument("output_image")
+parser.add_argument("radius", type=int)
+args = parser.parse_args()
+
+PixelType = itk.UC
+Dimension = 2
+
+ImageType = itk.Image[PixelType, Dimension]
+
+reader = itk.ImageFileReader[ImageType].New()
+reader.SetFileName(args.input_image)
+
+StructuringElementType = itk.FlatStructuringElement[Dimension]
+structuringElement = StructuringElementType.Ball(args.radius)
+
+grayscaleFilter = itk.GrayscaleFunctionDilateImageFilter[
+    ImageType, ImageType, structuringElement
+].New()
+grayscaleFilter.SetInput(reader.GetOutput())
+grayscaleFilter.SetKernel(structuringElement)
+
+writer = itk.ImageFileWriter[ImageType].New()
+writer.SetFileName(args.output_image)
+writer.SetInput(grayscaleFilter.GetOutput())
+
+writer.Update()

src/Filtering/MathematicalMorphology/DilateUsingFunctionalGrayscale/Documentation.rst

@@ -0,0 +1,52 @@
+:name: DilateUsingFunctionalGrayscale
+
+Dilate a grayscale image using a functional kernel
+========================
+
+.. index::
+  single: BinaryBallStructuringElement
+  single: GrayscaleFunctionDilateImageFilter
+  pair: mathematical morphology; dilation
+
+.. seealso:: dilation; erosion
+
+
+Synopsis
+--------
+
+Dilate an image using functional grayscale morphology.
+Function dilation takes the maximum of all the pixels identified by the structuring element plus the structuring element value.
+In this example, the white regions are enlarged.
+
+
+
+Results
+-------
+
+.. figure:: cthead1.png
+  :scale: 50%
+  :alt: Input ct head image.
+
+  Input grayscale image.
+
+.. figure:: OutputBaseline.png
+  :scale: 50%
+  :alt: Dilated output.
+
+  Dilated output.
+
+
+Code
+----
+
+C++
+...
+
+.. literalinclude:: Code.cxx
+   :lines: 18-
+
+
+Classes demonstrated
+--------------------
+
+.. breathelink:: itk::GrayscaleFunctionDilateImageFilter itk::BinaryBallStructuringElement

src/Filtering/MathematicalMorphology/DilateUsingFunctionalGrayscale/OutputBaseline.png.sha512

@@ -0,0 +1 @@
+92adb2cb8bc2437cf1451037aa14305e7302d31503059b2aa4bc53e4bc8cd8ad00cb43bcbb31097e058f2486d806037b9ac192227368368392efd8a5dbc5c77c

src/Filtering/MathematicalMorphology/DilateUsingFunctionalGrayscale/cthead1.png.sha512

@@ -0,0 +1 @@
+32d5c12cd02f537c901ee48ad2f438fcf5399f7292bf9c0abfb8da91b74fc2e0c4983e9650283db3462d22f05f05a8637a6c3b8188159e4bbd6dc68804a84870