[Insight-users] Re: Gradient of Vector Image

[Bing Jian]

Below is the orginal definition of GradientImageFilter from
\BasicFilters\itkGradientImageFilter.h

template <class TInputImage, class TOperatorValueType=float, class
TOutputValueType=float>
class ITK_EXPORT GradientImageFilter :
    public ImageToImageFilter< TInputImage,
                               Image<CovariantVector<TOutputValueType,
::itk::GetImageDimension<TInputImage>::ImageDimension>,
::itk::GetImageDimension<TInputImage>::ImageDimension> >

Assume in 3d case, we can see the default pixel type of outputimage of
gradientfilter is CovariantVector<float, 3>. If we take gradient again
on this output gradient, what kind of pixel type should we expect?
CovariantVector<float,9> or
<CovariantVector<CovariantVector<float,3>>,3>?

Thanks!


-- 
Best wishes,
Bing Jian
bjian at cise . ufl . edu


On Thu, 2 Oct 2003, Bing Jian wrote:

>
> Hi, Here is a question about gradient image.
>
> Suppose I have a vector image which is obtained from
> the output of gradientfilter applied on a scalar 3D
> image. Now the dimension of vector is 3. Can I take
> this vector image as input to the gradientfilter again?
> My expected output image should be a 3d vector image.
> And here the dimension of the vector should be 3*3=9,
> as the Jacobian of the original gradient image.
>
> Thanks in advance!
>
>