[Insight-developers] Odd filter/writer behavior

[Michael Stauffer]

Mac OSX 10.5.8
GCC 4.0.1
ITK 3.20

Hi,

I'm seeing odd behavior with a simple filter I made. The filter simply moidifies the Direction and Origin members of an input image and returns a new image. 

The printing the new image's modified Direction to stdout shows the correct values. But when I then write to a new image file, the modified Direction and Origin values only show up if the filter had been instantiated and used within a code block. I've attached source files for the filter and test, and included the relevant source snippet below. 

Note that in the second case, outputImage2->GetDirection()  prints with correct values, but the files that's subsequently written does not. Seems very odd. I see the same behavior in another test program.

Anyone have any ideas?

source:

  typedef itk::ComposeAffineTransformWithHeaderTransformImageFilter<ImageType,TransformType > ComposeFilterType;

  /////////////////////////////////////////////////////////////////////////    
  std::cout << "test2DHeader... filter code in block..." << std::endl;  
  
{ //This works when bracketed

  // Apply transform - this filter applies its inverse
  ComposeFilterType::Pointer composeFilter = ComposeFilterType::New();
  composeFilter->SetInput( inputImage );
  composeFilter->SetTransform( transform );
  composeFilter->Update();
  
  // Create output
  outputImage1 = composeFilter->GetOutput();
  }

  std::cout << "test2DHeader... outputImage1.Direction: " << std::endl;
  std::cout << outputImage1->GetDirection() << std::endl;
    
  // write it out
  typedef itk::ImageFileWriter<ImageType> WriterType;
  WriterType::Pointer writer1 = WriterType::New();
  writer1->SetFileName( "testBlock_"+outputfilename );
  writer1->SetInput( outputImage1 );
  writer1->Update();

  /////////////////////////////////////////////////////////////////////////
  std::cout << "test2DHeader... filter code WITHOUT block..." << std::endl;  
  // Apply transform - this filter applies its inverse

  ComposeFilterType::Pointer composeFilter = ComposeFilterType::New();
  composeFilter->SetInput( inputImage );
  composeFilter->SetTransform( transform );
  composeFilter->Update();
  
  // Create output
  outputImage2 = composeFilter->GetOutput();

  std::cout << "test2DHeader... outputImage2.Direction: " << std::endl;
  std::cout << outputImage2->GetDirection() << std::endl;
    
  // write it out
  //typedef itk::ImageFileWriter<ImageType> WriterType;
  WriterType::Pointer writer2 = WriterType::New();
  writer2->SetFileName( "testNoBlock_"+outputfilename );
  writer2->SetInput( outputImage2 );
  writer2->Update();
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