[ITK-users] Filter working on both itk::Image and itk::VectorImage

[Cyril Mory]

Hi,

Still the same topic, but a different issue:

I have a filter that is templated over its image input type, usually 
itk::Image<T, dim>. I want to modify it so that it also works when that 
type is itk::VectorImage<T, dim>.

This filter internally defines SliceType = 
itk::Image<InputImageType::InternalPixelType, dim - 1>. But when 
processing an itk::VectorImage, I would like this SliceType to be 
itk::VectorImage<InputImageType::InternalPixelType, dim - 1>.

I don't think there is a way in C++ to recover the itk::Image<> or the 
itk::VectorImage<> "un-templated", and define a type with whole new 
template arguments. But is there an ITK mechanism that would solve my 
problem ?

Best regards,

Cyril

On 22/02/2017 17:39, Matt McCormick wrote:
> Hi Cyril,
>
> Yes, this is a good approach.  Thanks for sharing your investigation.
>
> Matt
>
> On Wed, Feb 22, 2017 at 5:52 AM, Cyril Mory
> <cyril.mory at creatis.insa-lyon.fr> wrote:
>> Answering my own question:
>>
>> I found a way to do what I needed using itk::NumericTraits<T> :
>>
>>    OutputImagePixelType pix;
>>    itk::NumericTraits<OutputImagePixelType>::SetLength(pix,
>> this->GetVectorLength());
>>    pix = itk::NumericTraits<OutputImagePixelType>::OneValue(pix) * value;
>>
>> It works for both cases with the same code. However, if there is a better
>> way (cleaner, safer, more compact, ... whatever the wayin which it is
>> better), I'd be happy to learn about it.
>>
>> Best regards,
>> Cyril
>>
>>
>> On 22/02/2017 10:38, Cyril Mory wrote:
>>> Hi ITK users,
>>>
>>> I am writing an itk::ImageToImageFilter<T>, and I want the filter to work
>>> with T=itk::Image as well as with T=itk::VectorImage.
>>>
>>> To set/get the vectorLength of an image (which is 1 for an itk::Image, and
>>> varies for an itk::VectorImage), I have successfully used the functions
>>> Set/GetNumberOfComponentsPerPixel from the itk::ImageBase class, which work
>>> for both itk::Image and itk::VectorImage.
>>>
>>> But I cannot find a way to initialize one of the pixels to a given value,
>>> that would work for both cases, i.e. whether that pixel is a scalar or a
>>> variableLengthVector. For now, the best I could do is define a function
>>> FillPixel in my filter, like this:
>>>
>>> OutputImagePixelType FillPixel(OutputImageInternalPixelType value) {return
>>> value;}
>>>
>>> and write a template specialization when my filter is instantiated with
>>> itk::VectorImage<float, 3>, like this:
>>>
>>> template <>
>>> itk::VariableLengthVector<float>
>>> rtk::ConstantImageSource<itk::VectorImage<float, 3> >
>>> ::FillPixel(float value)
>>> {
>>>    itk::VariableLengthVector<float> vect;
>>>    vect.SetSize(this->GetVectorLength());
>>>    vect.Fill(value);
>>>    return (vect);
>>> }
>>>
>>> Did I miss something ? Is there a better way of doing this in ITK ?
>>>
>>> Looking forward to reading you,
>>> Cyril
>>>
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>>
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