DOC: add hill shading example

Examples/BasicFilters/HillShadingExample.cxx

+/*=========================================================================
+
+  Program:   ORFEO Toolbox
+  Language:  C++
+  Date:      $Date$
+  Version:   $Revision$
+
+
+  Copyright (c) Centre National d'Etudes Spatiales. All rights reserved.
+  See OTBCopyright.txt for details.
+
+
+     This software is distributed WITHOUT ANY WARRANTY; without even
+     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+     PURPOSE.  See the above copyright notices for more information.
+
+=========================================================================*/
+#if defined(_MSC_VER)
+#pragma warning ( disable : 4786 )
+#endif
+
+#ifdef __BORLANDC__
+#define ITK_LEAN_AND_MEAN
+#endif
+
+
+//  Software Guide : BeginCommandLineArgs
+//  OUTPUTS: {HillShadingExample.png}, {HillShadingColorExample.png}
+//  6.5 45.5 500 500 0.002 -0.002 ${OTB_DATA_ROOT}/Examples/DEM_srtm
+//  Software Guide : EndCommandLineArgs
+
+// Software Guide : BeginLatex
+//
+// Visualization of digital elevation models (DEM) is often more intuitive by simulating a
+// lighting source and generating the corresponding shadows. This principle is called
+// hill shading.
+//
+// Using a simple functor \doxygen{otb}{HillShadingFunctor} and the dem image generated
+// using the \doxygen{otb}{DEMToImageGenerator} (refer to \ref{sec:ReadDEM}) you can easily
+// obtain a representation of the DEM. Better yet, using the
+// \doxygen{otb}{ScalarToRainbowRGBPixelFunctor}, combined with the
+// \doxygen{otb}{ReliefColormapFunctor} you can easily generate the classic elevation maps.
+//
+// This example will focus on the shading itself.
+//
+// Software Guide : EndLatex
+
+
+#include "otbImage.h"
+#include "otbImageFileReader.h"
+#include "otbStreamingImageFileWriter.h"
+
+#include "otbDEMToImageGenerator.h"
+#include "otbHillShadingFunctor.h"
+#include "otbUnaryFunctorNeighborhoodImageFilter.h"
+
+#include "itkScalarToRGBColormapImageFilter.h"
+#include "otbReliefColormapFunctor.h"
+#include "itkMultiplyImageFilter.h"
+#include "itkBinaryFunctorImageFilter.h"
+#include "itkRescaleIntensityImageFilter.h"
+
+namespace otb {
+namespace Functor {
+
+template< class TInput1, class TInput2=TInput1, class TOutput=TInput1>
+class MultRGB
+{
+public:
+  MultRGB() {}
+  ~MultRGB() {}
+
+  inline TOutput operator()( const TInput1 & A, const TInput2 & B) const
+  {
+    TOutput out;
+    out.SetRed(A.GetRed() * B);
+    out.SetGreen(A.GetGreen() * B);
+    out.SetBlue(A.GetBlue() * B);
+    return out;
+  }
+};
+}
+}
+
+int main(int argc, char * argv[])
+{
+
+  if (argc != 10)
+  {
+    std::cout << argv[0] <<" <output_filename> <output_filename> ";
+    std::cout << " <Longitude Output Origin point> <Latitude Output Origin point>";
+    std::cout << " <X Output Size> <Y Output size>";
+    std::cout << " <X Spacing> <Y Spacing> <DEM folder path>"  << std::endl;
+    return EXIT_FAILURE;
+  }
+
+
+  typedef double                                         PixelType;
+  typedef unsigned char                                  UCharPixelType;
+  typedef itk::RGBPixel<UCharPixelType>                  RGBPixelType;
+  typedef otb::Image<PixelType, 2>                       ImageType;
+  typedef otb::Image<RGBPixelType, 2>                    RGBImageType;
+  typedef otb::Image<UCharPixelType, 2>                  ScalarImageType;
+  typedef otb::StreamingImageFileWriter<RGBImageType>    WriterType;
+  typedef otb::StreamingImageFileWriter<ScalarImageType> ScalarWriterType;
+
+  ScalarWriterType::Pointer writer = ScalarWriterType::New();
+  writer->SetFileName(argv[1]);
+
+  WriterType::Pointer writer2 = WriterType::New();
+  writer2->SetFileName(argv[2]);
+
+  typedef otb::DEMToImageGenerator<ImageType>      DEMToImageGeneratorType;
+
+  DEMToImageGeneratorType::Pointer demToImage = DEMToImageGeneratorType::New();
+
+  typedef DEMToImageGeneratorType::SizeType        SizeType;
+  typedef DEMToImageGeneratorType::SpacingType     SpacingType;
+  typedef DEMToImageGeneratorType::DEMHandlerType  DEMHandlerType;
+  typedef DEMHandlerType::PointType                PointType;
+
+  demToImage->SetDEMDirectoryPath(argv[9]);
+
+  PointType origin;
+  origin[0] = ::atof(argv[3]);
+  origin[1] = ::atof(argv[4]);
+
+  demToImage->SetOutputOrigin(origin);
+
+  SizeType size;
+  size[0] = ::atoi(argv[5]);
+  size[1] = ::atoi(argv[6]);
+
+  demToImage->SetOutputSize(size);
+
+  SpacingType spacing;
+  spacing[0] = ::atof(argv[7]);
+  spacing[1] = ::atof(argv[8]);
+
+  demToImage->SetOutputSpacing(spacing);
+
+  // Software Guide : BeginLatex
+  //
+  // After generating the dem image as in the DEMToImageGenerator example, you can declare
+  // the hill shading mechanism. The hill shading is implemented as a functor doing some
+  // operations in its neighorhood. This functor is used in the
+  // \doxygen{otb}{UnaryFunctorNeighborhoodImageFilter} that will be in charge of processing
+  // the whole image.
+  //
+  // Software Guide : EndLatex
+
+  // Software Guide : BeginCodeSnippet
+  typedef itk::ConstNeighborhoodIterator<ImageType>   IterType;
+  typedef otb::Functor::HillShadingFunctor<IterType, ImageType, PixelType> FunctorType;
+  typedef otb::UnaryFunctorNeighborhoodImageFilter<ImageType, ImageType, FunctorType> HillShadingFilterType;
+  HillShadingFilterType::Pointer hillShading = HillShadingFilterType::New();
+  hillShading->SetRadius(1);
+  hillShading->SetInput(demToImage->GetOutput());
+  // Software Guide : EndCodeSnippet
+
+
+  typedef itk::RescaleIntensityImageFilter<ImageType, ScalarImageType> RescalerType;
+  RescalerType::Pointer rescaler = RescalerType::New();
+  rescaler->SetOutputMinimum(0);
+  rescaler->SetOutputMaximum(255);
+  rescaler->SetInput(hillShading->GetOutput());
+
+  writer->SetInput(rescaler->GetOutput());
+
+
+  typedef itk::ScalarToRGBColormapImageFilter<ImageType,RGBImageType> ColorMapFilterType;
+  ColorMapFilterType::Pointer colormapper = ColorMapFilterType::New();
+  colormapper->UseInputImageExtremaForScalingOff();
+
+  typedef otb::Functor::ReliefColormapFunctor<PixelType, RGBPixelType> ColorMapFunctorType;
+  ColorMapFunctorType::Pointer colormap = ColorMapFunctorType::New();
+  colormap->SetMinimumInputValue(0);
+  colormap->SetMaximumInputValue(4000);
+  colormapper->SetColormap(colormap);
+
+  colormapper->SetInput(demToImage->GetOutput());
+
+
+  typedef itk::BinaryFunctorImageFilter<RGBImageType, ImageType, RGBImageType,
+    otb::Functor::MultRGB<RGBPixelType, PixelType, RGBPixelType> > MultiplyFilterType;
+
+  MultiplyFilterType::Pointer multiply = MultiplyFilterType::New();
+  multiply->SetInput1(colormapper->GetOutput());
+  multiply->SetInput2(hillShading->GetOutput());
+
+
+  writer2->SetInput(multiply->GetOutput());
+
+  try
+  {
+    writer->Update();
+    writer2->Update();
+  }
+  catch ( itk::ExceptionObject & excep )
+  {
+    std::cerr << "Exception caught !" << std::endl;
+    std::cerr << excep << std::endl;
+  }
+  catch ( ... )
+  {
+    std::cout << "Unknown exception !" << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  // Software Guide : BeginLatex
+  //
+  // Figure~\ref{fig:HILL_SHADING} shows the hill shading result from SRTM data.
+  //
+  // \begin{figure}
+  // \center
+  // \includegraphics[width=0.44\textwidth]{HillShadingExample.eps}
+  // \includegraphics[width=0.44\textwidth]{HillShadingColorExample.eps}
+  // \itkcaption[Hill shading]{Hill shading obtained from SRTM data (left) and combined with
+  // the color representation (right)}
+  // \label{fig:HILL_SHADING}
+  // \end{figure}
+  //  Software Guide : EndLatex
+
+  return EXIT_SUCCESS;
+}