[Insight-users] PixelType Doubt

[Daniela Sacchetto]

Thanks a lot, your mail was very useful for me.

 

Regards,

Daniela
 


Date: Sun, 12 Sep 2010 13:10:29 -0400
Subject: Re: [Insight-users] PixelType Doubt
From: luis.ibanez at kitware.com
To: danysunflower at hotmail.it
CC: insight-users at itk.org


Hi Daniela,


In genera you should use:


  A) signed short int   for     CT
  B) float                   for     PET
  C) signed shoft int   for     MRI

I'm not sure about US, but I would expect
that "unsigned char" will be a good fit.



Please take a look at the Insight Journal paper:

http://www.insight-journal.org/browse/publication/146



and the code in:

   InsightApplications/Auxiliary/vtk
                                  vtkKWImageIO.cxx



You will see how you can query the actual
pixel type of a DICOM file, and then instantiate
the appropriate pixel type for it.

Look at the "ReadAndCast()" method in lines 465-558:



  imageIO->SetFileName( this->FileName.c_str() );
  imageIO->ReadImageInformation();

  ScalarPixelType pixelType = imageIO->GetComponentType();

  // Use the pixel type to instantiate the appropriate reader
  switch( pixelType )
    {
    case itk::ImageIOBase::UCHAR:
      {
      this->ImageThatHasBeenRead = ReadAndCastMacro( unsigned char ); 
      this->ImagePixelType = UNSIGNED_CHAR;
      break;
      }

...etc.



   Regards


         Luis



---------------------------------------------------

On Thu, Sep 9, 2010 at 3:26 AM, Daniela Sacchetto <danysunflower at hotmail.it> wrote:


Hi everyone,
I'm writing because I have a question for you.
Could anyone explain me how can I decide the itk::PixelType? Usually I work with unsigned short pixels, but now I would like to understand better this problem.
 
For ex I know that:
 
PixelType must be "signed" for CT since Hounsfield units can be < 0.
 
Are there any rules for each medical image? (TC,PET,US,RX,...)
And when do you use pixelType = unsigned char?
 
Thanks all for your help,
Regards
Daniela

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