# Build Simple Functions

**URL:** https://discourse.itk.org/t/build-simple-functions/5956
**Category:** Algorithms
**Created:** [May 18, 2023, 10:57pm UTC](https://discourse.itk.org/t/build-simple-functions/5956 "2023-05-18T22:57:39Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Oddone-Scatena](https://discourse.itk.org/user_avatar/discourse.itk.org/oddone-scatena/32/2651_2.png) [@Oddone-Scatena](https://discourse.itk.org/u/Oddone-Scatena)
#### Post date: [May 18, 2023, 10:57pm UTC](https://discourse.itk.org/t/build-simple-functions/5956/1 "2023-05-18T22:57:40Z")

</div>

Hi, I would like to know what is wrong with this function:

I get :

thanks

Segment\_Bone(typename TImage::Pointer input, typename TImage::Pointer output,double bone\_threshold\_factor\_percentage)  
| ^ ~~~~~~~~~~~  
template argument deduction/substitution failed:  
couldn’t deduce template parameter ‘TImage’

```
    template <typename TImage>
    void
    Segment_Bone(typename TImage::Pointer input, typename TImage::Pointer output,double bone_threshold_factor_percentage)
    {
        
        using PixelType_Bone_Reader = typename TImage::PixelType;
        constexpr unsigned short Dimension = 3;
        using ImageType_Bone_Reader = itk::Image<TImage, Dimension>;
     
        using RescaleType_Bone = itk::RescaleIntensityImageFilter<TImage, TImage>;
        using Minimum_Bone_Type = itk::MinimumMaximumImageFilter<TImage>;
        using Threshold_Bone_Type = itk::BinaryThresholdImageFilter<TImage, TImage>;

    
      auto Rescale_Bone = RescaleType_Bone::New();
      Rescale_Bone->SetInput(input);
      Rescale_Bone->SetOutputMinimum(-1000);
      Rescale_Bone->SetOutputMaximum(1000);

      auto Minimum_Bone = Minimum_Bone_Type::New();
      Minimum_Bone->SetInput(Rescale_Bone->GetOutput());
      
      const PixelType_Bone_Reader ImageHighestIntensity_Bone = Minimum_Bone->GetMaximum() ;
      Minimum_Bone->Update();

      auto Threshold_Bone = Threshold_Bone_Type::New();
      Threshold_Bone->SetInput(Rescale_Bone->GetOutput());

      const PixelType_Bone_Reader outsideValue_Bone = 0;
      const PixelType_Bone_Reader insideValue_Bone = 255;

          Threshold_Bone->SetOutsideValue(outsideValue_Bone);
          Threshold_Bone->SetInsideValue(insideValue_Bone);

          const PixelType_Bone_Reader lowerThreshold_Bone = (Minimum_Bone->GetMaximum())*bone_threshold_factor_percentage;
          const PixelType_Bone_Reader upperThreshold_Bone = Minimum_Bone->GetMaximum();

          std::cerr << "Lower Threshold for Bones: " <<lowerThreshold_Bone<< " Upper Threshold for Bones: " <<upperThreshold_Bone<< std::endl;
          Threshold_Bone->SetLowerThreshold(lowerThreshold_Bone);
          Threshold_Bone->SetUpperThreshold(upperThreshold_Bone);
          Threshold_Bone->Update();
          
          output = Threshold_Bone->GetOutput();
          
          }

```

in the main program:

```
  using PixelType_Bone_Reader = signed short;
        using ImageType_Bone_Reader = 
itk::Image<PixelType_Bone_Reader, Dimension>;

        using ReaderType_Bone = itk::ImageSeriesReader<ImageType_Bone_Reader>;
        using CastFilter_Bone_Type = itk::CastImageFilter<ImageType_Bone_Reader, ImageType>;        
        using WriterType_Bone = itk::ImageFileWriter<ImageType>;
 
       auto reader_Bone = ReaderType_Bone::New();
       reader_Bone->SetImageIO(gdcmIO);
       reader_Bone->SetFileNames(filenames);

       auto reader_Bone_2 = ReaderType_Bone::New();
       reader_Bone_2->SetImageIO(gdcmIO);
       reader_Bone_2->SetFileNames(filenames);

       try{reader_Bone->Update();}
       catch (const itk::ExceptionObject & excp)
       {std::cerr << "Exception thrown while writing the image" << std::endl;std::cerr << excp << std::endl;
       return EXIT_FAILURE;}
       
        try{reader_Bone_2->Update();}
       catch (const itk::ExceptionObject & excp)
       {std::cerr << "Exception thrown while writing the image" << std::endl;std::cerr << excp << std::endl;
       return EXIT_FAILURE;}
       
        auto image_for_bone_segmentation = reader_Bone->GetOutput();
          
        auto segmented_bone_image = reader_Bone_2->GetOutput();
        segmented_bone_image->FillBuffer(0.0);

        segmented_bone_image->SetSpacing(spacing);
        segmented_bone_image->SetOrigin(newOrigin);
        segmented_bone_image->SetDirection(direction);   
          
        Segment_Bone(image_for_bone_segmentation, segmented_bone_image, bone_threshold_factor_percentage);
          
        auto CastFilter_Bone = CastFilter_Bone_Type::New();
        CastFilter_Bone->SetInput(segmented_bone_image);

        auto writer_bone = WriterType_Bone::New();
        writer_bone->SetFileName("SEGMENTED BONES.dcm");
        writer_bone->SetInput(CastFilter_Bone->GetOutput());
        writer_bone->Update();

```

---

<div class="post-metadata">

### Author: ![dzenanz](https://discourse.itk.org/user_avatar/discourse.itk.org/dzenanz/32/1093_2.png) [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [May 19, 2023, 1:45pm UTC](https://discourse.itk.org/t/build-simple-functions/5956/2 "2023-05-19T13:45:45Z")

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> [@Oddone-Scatena](#):
>
> `Segment_Bone(image_for_bone_segmentation, segmented_bone_image, bone_threshold_factor_percentage);`

This should be: `Segment_Bone<ImageType>(image_for_bone_segmentation, segmented_bone_image, bone_threshold_factor_percentage);` The change is `Segment_Bone(...)` to `Segment_Bone<ImageType>(...)`. Compiler isn’t smart enough to deduce this, so we have to write it explicitly.