[Insight-users] MaskImageFilter with VectorImage

[Cory Quammen]

David,

Unfortunately, it appears you cannot use the itk::MaskImageFilter on
vector images. The problem is in line 60 of itkMaskImageFilter.h, as
your error report says. The line defines the constructor as

MaskInput():m_OutsideValue(NumericTraits< TOutput >::Zero) {}

TOutput is a itk::VariableLengthVector< unsigned char, 2 >, which
means that the partial specialization of itk::NumericTraits for
itk::VariableLengthVector< T > is instantiated. In this
specialization, itk::NumericTraits<T>::Zero is a static method that
takes a reference vector pixel to determine the vector length at run
time, whereas for most built-in types itk::NumericTraits<T>::Zero is a
static member variable. Thus the complaint about not being able to
cast from a method to an unsigned int.

To make itk::MaskImageFilter work with vector images, you could write
a partial specialization of itk::Functor::MaskInput specifically for a
TOutput of type itk::VariableLengthVector< T > that doesn't have the
initialization of m_OutsideValue in the constructor definition. This
isn't ideal because it leaves the outside value uninitialized, but I
don't see what other option there is for vector images because the
vector length isn't known until run time.

Cory

On Tue, Apr 5, 2011 at 7:10 PM, David Doria <daviddoria at gmail.com> wrote:
> On Sun, Apr 3, 2011 at 12:43 PM, David Doria <daviddoria at gmail.com> wrote:
>>
>> When trying to compile this:
>>
>> #include "itkVectorImage.h"
>> #include "itkMaskImageFilter.h"
>>
>> typedef itk::VectorImage<unsigned char, 2>  VectorImageType;
>> typedef itk::Image<unsigned char, 2>  MaskImageType;
>>
>> int main(int argc, char *argv[])
>> {
>>  typedef itk::MaskImageFilter< VectorImageType, MaskImageType >
>> MaskFilterType;
>>  MaskFilterType::Pointer maskFilter = MaskFilterType::New();
>>  maskFilter->Update();
>>
>>  return EXIT_SUCCESS;
>> }
>>
>> I get
>> itkMaskImageFilter.h:60: error: invalid conversion from ‘const
>> itk::VariableLengthVector<unsigned char> (*)(const
>> itk::VariableLengthVector<unsigned char>&)’ to ‘unsigned int’
>> itkMaskImageFilter.h:60: error:   initializing argument 1 of
>> ‘itk::VariableLengthVector<TValueType>::VariableLengthVector(unsigned
>> int) [with TValueType = unsigned char]’
>>
>> Is there any reason a VectorImage cannot be masked?
>>
>> Thanks,
>>
>> David
>
> Is there a different class to mask a VectorImage?
>
> David
>
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-- 
Cory Quammen
Computer Integrated Systems for Microscopy and Manipulation (CISMM)
Department of Computer Science
University of North Carolina at Chapel Hill
http://www.cs.unc.edu/~cquammen