[Insight-users] Re: Re:VectorImage IO

[Karthik Krishnan]

Hi Bryn,

On Wed, 2005-08-24 at 19:32 -0400, Bryn Lloyd wrote:
> Hi Karthik,
> 
> If I understand correctly, you say VectorImages should be readable/writable?

Yes it is, with any file format that supports multi-component data such
as Metaimage, nrrd, vtk, ........

> 
> I think the IO does not work for VectorImages yet. I have added some
> simple code to this email to read and write a VectorImage. It does not
> compile!?

There is a test for that does IO with the VectorImage: Please take a
look at Testing/Code/Common/itkVectorImageTest.cxx.

The line you need to change to get this code to compile is:

So your code should read:

typedef itk::VectorImage< PixelType, Dimension > ImageType;
typedef itk::ImageFileReader< ImageType, itk::DefaultConvertPixelTraits<
PixelType > > ReaderType;

instead of

typedef itk::ImageFileReader< ImageType > ReaderType;

[The point being that you want the reader treating the VectorImage as a
multi-component 3 dimensional image with scalar pixels, rather than as a
3D image with Vector pixels.]

Yes I know that you may not be used to adding that extra word there, I
intend picking this up from as traits from the image itself, so you
won't have to do that in future, but I won't do that during before the
release.

Thanks 
Regards
Karthik


> 
> I want to write a test-program for Gordon to read/write Nrrd images into ITK.
> 
> Thanks!
> 
> Bryn
> 
> 
> ---------------------------
> #include <fstream>
> #include "itkImageFileReader.h"
> #include "itkImageFileWriter.h"
> #include "itkVectorImage.h"
> 
> 
> //int itkVectorImageNrrdReadWriteTest( int ac, char* av[] )
> int main( int ac, char* av[]  )
> {
>   if(ac < 2)
>     {
>     std::cerr << "Usage: " << av[0] << " Input Output\n";
>     return EXIT_FAILURE;
>     }
> 
>   typedef float PixelType;
>   typedef itk::VectorImage<PixelType, 2> myImage;
> 
> 
>   itk::ImageFileReader<myImage>::Pointer reader
>                                   = itk::ImageFileReader<myImage>::New();
>   reader->SetFileName(av[1]);
> 
>   try
>     {
>     reader->Update();
>     }
>   catch (itk::ExceptionObject & e)
>     {
>     std::cerr << "exception in file reader " << std::endl;
>     std::cerr << e.GetDescription() << std::endl;
>     std::cerr << e.GetLocation() << std::endl;
>     return EXIT_FAILURE;
>     }
> 
>   myImage::Pointer image = reader->GetOutput();
>   image->Print(std::cout );
> 
>   // Generate test image
>   itk::ImageFileWriter<myImage>::Pointer writer;
>   writer = itk::ImageFileWriter<myImage>::New();
>   writer->SetInput( reader->GetOutput() );
>   writer->SetFileName(av[2]);
>   try
>     {
>     writer->Update();
>     }
>   catch (itk::ExceptionObject & e)
>     {
>     std::cerr << "exception in file writer " << std::endl;
>     std::cerr << e.GetDescription() << std::endl;
>     std::cerr << e.GetLocation() << std::endl;
>     return EXIT_FAILURE;
>     }
> 
> 
>   return EXIT_SUCCESS;
> 
> }
> 
> 
>