[Insight-users] Function definition error

[Luis Ibanez]

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Hi Radhika,

ITK filters on GetOutput() return *raw* pointers to images
not SmartPointers. The reason for doing this is that the  filter
internally holds a smart pointer to its input.

You can receive a raw pointer into a SmartPointer of the
appropriate type. However the conversion is not enough
for the compiler to figure out that your templated function
matches the type.

You have the following options:

1) The arguments to the BSI() function should be

                itk::Image< PixelType, 3> *

    instead of

            itk::Image< PixelType, 3> ::Pointer

2) Even better, you could template the function over the
    image type as:

template <class TImageType>
float BSI2( TImageType * image1,  TImageType * image2,
            TImageType * mask1, TImageType * mask2,
            float i1,float i2,float K)


3) And you will have a longer and more pleasant life if you
     also embrace const-correctness, like in

   template <class TImageType>
  float BSI3( const TImageType * image1, const TImageType * image2,
              const TImageType * mask1,  const TImageType * mask2,
              float i1,float i2,float K)

    Since nobody is allowed to change the output of an ITK filter.


Please find attached a file with these three options.

I would encourage you to use the model of BSI3.



The best way to go though is to use classes instead of functions.
In this case, you can create a "Calculator" class which is a templated
class with an "Execute()" method.  You connect all the images as inputs
and then invoke the Execute() methods with no arguments.  


Regards,


      Luis

 
---------------------------------------
Radhika Sivaramakrishna wrote:

> Hi Luis,
> I was trying to define a function templated over the pixel type to 
> which four images along with some other numbers of type float are 
> passed and it returns a float.
> I am getting an error that I cannot understand. I am sure it is very 
> straightforward. Could you tell me whats the problem? I have enclosed 
> below the error I am getting, the way I am calling the function from 
> main and also how the function has been defined.
>  
> Radhika
>  
> error C2784: 'float __cdecl BSI(class itk::SmartPointer<class 
> itk::Image<PixelType,`template-parameter258'> >,class 
> itk::SmartPointer<class itk::Image<PixelType,`template-parameter258'> 
> >,class itk::SmartPoint
> er<class itk::Image<PixelType,`template-parameter258'> >,class 
> itk::SmartPointer<class itk::Image<PixelType,`template-parameter258'> 
> >,float,float,float)' : could not deduce template argument for 'class 
> itk::SmartPointer<class itk::Image<TObjectType
> ,`template-parameter258'> >' from 'class itk::Image<unsigned char,3> *'
>  
> int main()
> {
> ... 
>  
> float bsivalue = 
> BSI(readerimage1->GetOutput(),readerimage2->GetOutput(),readermask1->GetOutput(),readermask2->GetOutput(),i1,i2,K);  
>
> ...
> }
>  
> template <class PixelType> float BSI(itk::Image< PixelType, 
> 3>::Pointer image1,itk::Image< PixelType, 3>::Pointer 
> image2,itk::Image< PixelType, 3>::Pointer mask1,itk::Image< PixelType, 
> 3>::Pointer mask2,float i1,float i2,float K)
> {
> // Body of function
> }
>  
>  
>  

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Content-Type: text/x-c++src;
 name="Function.cxx"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="Function.cxx"

#include "itkImage.h" 
#include "itkImageFileReader.h"


typedef itk::Image< unsigned char, 3 > ImageType;

template <class PixelType> 
float BSI(typename itk::Image< PixelType, 3>::Pointer image1,
          typename itk::Image< PixelType, 3>::Pointer image2,
          typename itk::Image< PixelType, 3>::Pointer mask1,
          typename itk::Image< PixelType, 3>::Pointer mask2,
          float i1,float i2,float K)
{
 return 2.0;
}


template <class PixelType> 
float BSI(itk::Image< PixelType, 3> * image1,
          itk::Image< PixelType, 3> * image2,
          itk::Image< PixelType, 3> * mask1,
          itk::Image< PixelType, 3> * mask2,
          float i1,float i2,float K)
{
 return 2.0;
}

template <class TImageType> 
float BSI2( TImageType * image1,
            TImageType * image2,
            TImageType * mask1,
            TImageType * mask2,
            float i1,float i2,float K)
{
 return 2.0;
}

template <class TImageType> 
float BSI3( const TImageType * image1,
            const TImageType * image2,
            const TImageType * mask1,
            const TImageType * mask2,
            float i1,float i2,float K)
{
 return 2.0;
}


int main()
{

typedef itk::ImageFileReader< ImageType > FilterType;

FilterType::Pointer readerimage1 = FilterType::New();
FilterType::Pointer readerimage2 = FilterType::New();
FilterType::Pointer readermask1  = FilterType::New();
FilterType::Pointer readermask2  = FilterType::New();
 
float i1 = 1.0;
float i2 = 1.0;
float K  = 1.0;

float bsivalue = 
    BSI( readerimage1->GetOutput(), 
         readerimage2->GetOutput(),
         readermask1->GetOutput(),
         readermask2->GetOutput(),
         i1,i2,K); 

float bsivalue2 = 
    BSI2( readerimage1->GetOutput(), 
          readerimage2->GetOutput(),
          readermask1->GetOutput(),
          readermask2->GetOutput(),
          i1,i2,K); 

float bsivalue3 = 
    BSI3( readerimage1->GetOutput(), 
          readerimage2->GetOutput(),
          readermask1->GetOutput(),
          readermask2->GetOutput(),
          i1,i2,K); 


}

 
 
 


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