[Insight-developers] GDCM: How to find out the correct pixel type

[Mathieu Malaterre]

Hi everyone,

  I have finally implemented a fix for the issue with the slicer
plugin that would instanciate a INT or UINT itk::ImageFileReader where
a SHORT or USHORT would suffice. The fix was rather trivial

$ cvs ci -m"ENH: Fix feature request: 0006138: Finding proper pixel
type for DICOM is cumbersome" itkGDCMImageIO.cxx
/cvsroot/Insight/Insight/Code/IO/itkGDCMImageIO.cxx,v  <--  itkGDCMImageIO.cxx
new revision: 1.128; previous revision: 1.127

  At the same time I added a small example that would dump the
component type / pixel type needed to properly instanciate the
itk::ImageFileReader so that also ITK user can take advantage of it.
This should hopefully solve the issue where a user would not be aware
of the DICOM specification for storing pixel data:

$ cvs ci -m"ENH: Adding a piece of code to dump the correct pixel type
to instanciate the itk::ImageFileReader" DicomImageReadPrintTags.cxx
/cvsroot/Insight/Insight/Examples/IO/DicomImageReadPrintTags.cxx,v
<--  DicomImageReadPrintTags.cxx
new revision: 1.18; previous revision: 1.17

  So the problem here is that a piece code and a particular dataset in
Slicer would instanciated a INT itk::ImageFileReader, whereas now it
will instanciate a SHORT itk::ImageFileReader. Does this violate the
backwarc compatible policy ?


Thanks,
-Mathieu

On Nov 22, 2007 3:49 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
> Mathieu,
>
> Here is some code we use in Slicer3 plugins to determine pixel and component
> type at run-time:
>
> namespace itk
> {
>   // Description:
>   // Get the PixelType and ComponentType from fileName
>   void GetImageType (std::string fileName,
>                      ImageIOBase::IOPixelType &pixelType,
>                      ImageIOBase::IOComponentType &componentType)
>     {
>       typedef itk::Image<unsigned char, 3> ImageType;
>       itk::ImageFileReader<ImageType>::Pointer imageReader =
>         itk::ImageFileReader<ImageType>::New();
>       imageReader->SetFileName(fileName.c_str());
>       imageReader->UpdateOutputInformation();
>
>       pixelType = imageReader->GetImageIO()->GetPixelType();
>       componentType = imageReader->GetImageIO()->GetComponentType();
>     }
>
>   // Description:
>   // Get the PixelTypes and ComponentTypes from fileNames
>   void GetImageTypes (std::vector<std::string> fileNames,
>                       std::vector<ImageIOBase::IOPixelType> &pixelTypes,
>                       std::vector<ImageIOBase::IOComponentType>
> &componentTypes)
>     {
>     pixelTypes.clear();
>     componentTypes.clear();
>
>     // For each file, find the pixel and component type
>     for (std::vector<std::string>::size_type i = 0; i < fileNames.size();
> i++)
>       {
>       ImageIOBase::IOPixelType pixelType;
>       ImageIOBase::IOComponentType componentType;
>
>       GetImageType (fileNames[i],
>                     pixelType,
>                     componentType);
>       pixelTypes.push_back(pixelType);
>       componentTypes.push_back(componentType);
>       }
>     }
>   }
>
> Bill
>



-- 
Mathieu