Exemple streaming explicite

Examples/IO/CMakeLists.txt

@@ -6,6 +6,9 @@ TARGET_LINK_LIBRARIES(ImageReadWrite OTBCommon OTBIO ITKCommon ITKIO)
 ADD_EXECUTABLE(StreamingImageReadWrite StreamingImageReadWrite.cxx )
 TARGET_LINK_LIBRARIES(StreamingImageReadWrite OTBCommon OTBIO ITKCommon ITKIO)
 
+ADD_EXECUTABLE(ExplicitStreamingExample ExplicitStreamingExample.cxx )
+TARGET_LINK_LIBRARIES(ExplicitStreamingExample OTBCommon OTBIO ITKCommon ITKIO)
+
 
 ADD_EXECUTABLE(ImageReadCastWrite ImageReadCastWrite.cxx )
 TARGET_LINK_LIBRARIES(ImageReadCastWrite OTBCommon OTBIO ITKCommon ITKIO)

Examples/IO/ExplicitStreamingExample.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
+
+#include "otbVectorImage.h"
+#include "otbImageFileReader.h"
+#include "itkImageRegionConstIterator.h"
+//  Software Guide : BeginLatex
+//
+//  Usually, the streaming process is hidden within the pipeline. This
+//  allows the user to get rid of the annoying task of splitting the
+//  images into tiles, end so on. However, for some kinds of
+//  processing, we do not really need a pipeline: no writer is needed,
+//  only read access to pixel values is wanted. In these cases, one
+//  has to explicitly set up the streaming procedure. Fortunately, OTB
+//  offers a high level of abstraction for this task. We will need to
+//  include the following header files:
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet
+#include "itkImageRegionSplitter.h"
+#include "otbStreamingTraits.h"
+// Software Guide : EndCodeSnippet
+
+
+int main(int argc, char * argv[])
+{
+
+  if( argc != 3 )
+    {
+    std::cerr << "Usage: " << std::endl;
+    std::cerr << argv[0] << " inputImageFile nbLinesForStreaming " << std::endl;
+    return EXIT_FAILURE;
+    }
+
+
+  const char * infname = argv[1];
+  const unsigned int nbLinesForStreaming = atoi(argv[2]);
+
+  typedef float PixelType;
+
+  typedef otb::VectorImage<PixelType,2> ImageType;
+  typedef otb::ImageFileReader<ImageType> ImageReaderType;
+
+//  Software Guide : BeginLatex
+//
+//  The \doxygen{otb}{StreamingTraits} class manages the streaming
+//  approaches which are possible with the image type over which it is
+//  templated. The class \doxygen{itk}{ImageRegionSplitter} is
+//  templated over the number of dimensions of the image and will
+//  perform the actual image splitting.
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet
+  typedef otb::StreamingTraits<ImageType> StreamingTraitsType;
+  typedef itk::ImageRegionSplitter<2>  SplitterType;
+// Software Guide : EndCodeSnippet
+//  Software Guide : BeginLatex
+//
+//  Once a region of the image is available, we will use classical
+//  region iterators to get the pixels.
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet  
+  typedef ImageType::RegionType RegionType;
+
+  typedef itk::ImageRegionConstIterator<ImageType> IteratorType;
+// Software Guide : EndCodeSnippet
+//  Software Guide : BeginLatex
+//
+//  We instantiate the image file reader, but in order to avoid
+//  reading the whole image, we call the
+//  \code{GenerateOutputInformation()} method instead of the
+//  \code{Update()} one. \code{GenerateOutputInformation()} will make
+//  available the information about sizes, band, resolutions,
+//  etc. After that, we can access the largest possible region of the
+//  input image.
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet    
+  ImageReaderType::Pointer reader = ImageReaderType::New();
+
+  reader->SetFileName(infname);
+
+
+  reader->GenerateOutputInformation();
+  
+  RegionType largestRegion = reader->GetOutput()->GetLargestPossibleRegion();
+// Software Guide : EndCodeSnippet
+//  Software Guide : BeginLatex
+//
+//  We set up now the local streaming capabilities by asking the
+//  streaming traits to compute the number of regions to split the
+//  image into given the splitter, the user defined number of lines,
+//  and the input image information.
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet    
+  SplitterType::Pointer splitter = SplitterType::New();
+  unsigned int numberOfStreamDivisions =
+    StreamingTraitsType::CalculateNumberOfStreamDivisions(
+      reader->GetOutput(),
+      largestRegion,
+      splitter,
+      otb::SET_BUFFER_NUMBER_OF_LINES,
+      0,0,nbLinesForStreaming);
+// Software Guide : EndCodeSnippet
+  std::cout<<"The images will be streamed into "<<numberOfStreamDivisions<<" parts."<<std::endl;
+ 
+
+//  Software Guide : BeginLatex
+//
+//  We can now get the split regions and iterate through them.
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet    
+  
+  unsigned int piece = 0;
+  RegionType streamingRegion;
+
+
+  for (piece = 0;
+       piece < numberOfStreamDivisions;
+       piece++)
+  {
+// Software Guide : EndCodeSnippet
+//  Software Guide : BeginLatex
+//
+//  We get the region
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet      
+    streamingRegion =
+      splitter->GetSplit(piece,numberOfStreamDivisions,largestRegion);
+
+    std::cout<<"Processing region: "<<streamingRegion<<std::endl;
+// Software Guide : EndCodeSnippet
+//  Software Guide : BeginLatex
+//
+//  We ask the reader to provide the region.
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet          
+      
+    reader->GetOutput()->SetRequestedRegion(streamingRegion);
+    reader->GetOutput()->PropagateRequestedRegion();
+    reader->GetOutput()->UpdateOutputData();
+// Software Guide : EndCodeSnippet
+//  Software Guide : BeginLatex
+//
+//  We declare an iterator and walk through the region.
+//
+//  Software Guide : EndLatex 
+
+// Software Guide : BeginCodeSnippet          
+      
+    IteratorType it(reader->GetOutput(),streamingRegion);
+    it.GoToBegin();
+
+    while(!it.IsAtEnd())
+    {
+    std::cout << it.Get() << std::endl;
+    ++it;
+    }
+
+// Software Guide : EndCodeSnippet    
+  }
+    return EXIT_SUCCESS;
+}