[Insight-users] I can't show Pixel Value! Did i make a mistake using iterators

[Pingkun Yan]

Hi charfeddine,

I am not sure if the problem is caused by
m_thresholdregionsize[2]=0;
Maybe you should set it to 1.

In fact, you have a better choice. You can use the ITK extract slice
filter, which will extract one slice from a volume. You can find
examples in ITK. Then you just need to use a 2D image iterator to read
this 2D slice, which will be much easier.

HTH,
Pingkun

On 2/9/06, charfeddine amir <charfeddine_amir at yahoo.fr> wrote:
> Hi all
>  I'm reading Dicom file containing many slice, from which i extract one
> slice.
>  when i try to show the contenent of the image extracted (pixel value) using
> iterators i get a black screen, and when i try GetPixel method( which is too
> slow), i can show the value.
>  did i make a mistake somewhere!
>
>  this is the code
>
> /************************************************************************************/
>  typedef   itk::Image<float,3>    InputImageType;
>  typedef itk::Image< float, 2 > DiasstolImageType;
>
>  typedef itk::ImageRegionConstIterator< InputImageType > ConstIteratorType;
>  typedef itk::ImageRegionIterator< DiasstolImageType>       IteratorType;
>
>  .....
> m_thresholdregion=m_OutputImage->GetLargestPossibleRegion();
>  ThresholdedImageType::SizeType m_thresholdregionsize=
> m_thresholdregion.GetSize();
>  m_thresholdregionsize[2]=0;
>
>  ThresholdedImageType::IndexType m_thresholdregionstart =
> m_thresholdregion.GetIndex();
>  m_thresholdregionstart[2]=slicenumber;
>
>  m_thresholddesiredregion.SetSize( m_thresholdregionsize );
>  m_thresholddesiredregion.SetIndex( m_thresholdregionstart
> );
>
>
> std::cout<<std::endl<<"---------------------------------->incidence
> N°"<<card<<std::endl;
>
>
>  ConstIteratorType in(   m_OutputImage, m_thresholddesiredregion );
>  IteratorType      out(  m_DiasstoledImage, m_diasstoledimageregion );
>  for ( in.GoToBegin(), out.GoToBegin(); !in.IsAtEnd(); ++in, ++out)
>    {
>    out.Set( in.Get() );
>    std::cout<<in.Get()<<" - ";
>    }
>
> /*******************************************************************************/
>  i get this screen on execution:
>
>  La diasstole de l'incidence courante est l'image 0
>
>  ---------------------------------->incidence N°0
>
>  **********************************Incidence
> suivante****************************
>
>  La diasstole de l'incidence courante est l'image 0
>
>  ---------------------------------->incidence N°1
>
>  **********************************Incidence
> suivante****************************
>
> /*******************************************************************************************/
>  But if remplace the use of iterators loop with this classic one :
>
>  pixelIndex[2]=slicenumber;
>  for(j=0; j<m_inputimagesize[1]; j++)
>       {
>        pixelIndex[1]=j;
>        m_diasstoledimageindex[1]=j;
>        for(i=0; i<m_inputimagesize[0]; i++)
>        {
>         m_diasstoledimageindex[0]=i;
>         pixelIndex[0]=i;
>         pixelValue = m_OutputImage->GetPixel( pixelIndex );
>
> m_DiasstoledImage->SetPixel(m_diasstoledimageindex,pixelValue);
>         std::cout<<pixelValue<<" - ";
>        }
>       }
>
>  I get the next screen:
>
>  La diasstole de l'incidence courante est l'image 0
>  0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 -
> 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 -
> 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 -
> 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 -
> 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 -
> 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255
> - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 -
> 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255
> - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 -
> 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255
> - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 - 255 -
> 255 - 255 - 255 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0
> - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0 - 0
> - 0 -.........
>
>  any comment is welcome
>  thx
>  amir
>
>
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