[Insight-users] problem with defining public Filter objects

[Luis Ibanez]

Hi Seniha,

It seems that you are misusing the SetSize() method
of the ImageRegion class.

The argument for this method are not Width,Height
as you are providing in your code.
Instead, they are:

        SetSize( dimension, size );


This is because ITK supports N-Dimensional images,
not just 2D images.


Your code should be:

   regionGL.SetSize(0,Width );  // dimension 0 is X
   regionGL.SetSize(1,Height);  // dimension 1 is Y

and

   regionGL.SetIndex(0,0);  // index in X
   regionGL.SetIndex(1,0);  // index in Y


You can also follow the example illustrated in the
ITK Software Guide

     http://www.itk.org/ItkSoftwareGuide.pdf

where objects for Index and Size are explicitly created,
and initialized, like

    RegionType::IndexType start;
    start[0] = 0;  // dimension X
    start[1] = 0;  // dimension Y

    RegionType::SizeType size;
    size[0] = Width; // dimension X
    size[1] = Width; // dimension Y

    regionGl.SetSize( size );
    regionGl.SetIndex( start );


This is a bit verbose, but it is much clearer.


   Regards,


      Luis



-------------------------
Seniha Esen Yuksel wrote:
> Hi all,
> I want to define a public filter in my function which I will use as 
> a buffer to hold my images, but I am getting an exception error. 
> Actually even before the exception error, I can see that the  output of 
> the filter is empty, which makes me think that I am defining the 
> RegionType in a wrong way -- could you please particularly look at that 
> and tell me if it is correct?   I am copying parts of the code below 
> from the header file and the c++ file.
>  
> //------------------------------------------------------------------------------
> //part of the code from my .h file:
> //------------------------------------------------------------------------------
>  
> public:
>  
> // ........
>  
> //===================
> //My ITK Object Pointers
> //===================
>    
>   typedef int integer;
>   typedef unsigned short      PixelType;
>   typedef  unsigned char  InputPixelType;
>   typedef  unsigned char  OutputPixelType;
>   typedef itk::Image< InputPixelType,  2 >   InputImageType;
>   typedef itk::Image< OutputPixelType, 2 >   OutputImageType;
>   typedef itk::RegionOfInterestImageFilter<InputImageType, 
> OutputImageType >  FilterType;
>   typedef itk::ImageFileWriter< OutputImageType> WriterTypeGL;
> 
>   FilterType::Pointer filter;
>   WriterTypeGL::Pointer writergl;
>  
>  InputImageType::RegionType regionGL;
> // ........
>  
>  
> //------------------------------------------------------------------------------
> //-------------------- part of my c++ code --------------------------
>  
> int FrontDialog::CropImage(){
>  
> //...........................
>  
>  writerMoving->SetFileName( output.c_str() );
>  writerMoving->SetInput( cropMoving->GetOutput() );
>  try {
>          writerMoving->Update();
>          }     catch (itk::ExceptionObject &err)         {
>          std::cout<< "Exception caught:" << std::endl;
>          std::cout<< err <<std::endl;
>        
>          return -1;
>          }
>  
> //here I definitely know that cropMoving->GetOutput()  gives correct results
> //because I am able to save it as an image. However, I also want to save 
> it in a
> //public variable to use over and over.
>  
> //here comes the part which fails:
>  
>  regionGL.SetSize(Width, Height);
>  regionGL.SetIndex(0,0);
> 
>  filter = FilterType::New();
>  filter->SetRegionOfInterest(regionGL);
>  filter->SetInput( crop->GetOutput());
>  try {
>           filter->Update();
>          }     catch (itk::ExceptionObject &err)         {
>          std::cout<< "Exception caught:" << std::endl;
>          std::cout<< err <<std::endl;
>        
>          return -1;
>          }
> 
>  filter->GetOutput()->Print( std::cout );
>  
> //.............
> return 0;
> }
>  
>  
> //-------------------------------------------------------------------
>  
>  
> I spent too much time to figure out this problem but I am now clueless 
> on what to do. The output of the exe file is as below.  I will really 
> appreciate it a lot if anyone could help me...
> Thanks a lot in advance,
> Seniha
>  
>  
> This program resizes the input file with the following parameters
> x starting value: 300
> y starting value: 300
> x extension     : 200
> y extension     : 200
> ===========================
> images are cropped
> Image (02695AA0)
>   RTTI typeinfo:   class itk::Image<unsigned char,2>
>   Reference Count: 1
>   Modified Time: 236
>   Debug: Off
>   Observers:
>     none
>   Source: (02695B90)
>   Source output index: 0
>   Release Data: Off
>   Data Released: False
>   Global Release Data: Off
>   PipelineMTime: 222
>   UpdateMTime: 237
>   LargestPossibleRegion:
>     Dimension: 2
>     Index: [0, 0]
>     Size: [0, 0]
>   BufferedRegion:
>     Dimension: 2
>     Index: [0, 0]
>     Size: [0, 0]
>   RequestedRegion:
>     Dimension: 2
>     Index: [0, 0]
>     Size: [0, 0]
>   Spacing: [1, 1]
>   Origin: [300, 300]
>   PixelContainer:
>     ImportImageContainer (02694BE0)
>       RTTI typeinfo:   class itk::ImportImageContainer<unsigned 
> long,unsigned ch
> ar>
>       Reference Count: 1
>       Modified Time: 235
>       Debug: Off
>       Observers:
>         none
>       Pointer: 02694C10
>       Container manages memory: true
>       Size: 0
>       Capacity: 0
> Exception caught:
> itk::ExceptionObject (0109E4C0)
> Location: "Unknown"
> File: 
> C:\ITK\InsightToolkit-2.0.0\InsightToolkit-2.0.0\Code\IO\itkPNGImageIO.cxx
> Line: 395
> Description: itk::ERROR: PNGImageIO(026955F0): PNG Writer can only write 
> 2-dimen
> sional images
> 
>  
> 
> 
> Seniha Esen Yuksel
> Research Assistant
> Computer Vision and Image Processing Lab,
> Lutz Hall Rm 414,
> University of Louisville,
> Louisville, KY
> work ph: 502- 8521528
> home ph: 502- 8549856
> email: esen at cvip.uofl.edu // esenyuksel at ieee.org
> web: http://www.cvip.louisville.edu/~esen/
> 
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