[Insight-users] HessianRecursiveGaussianImageFilter

[Won-Ki Jeong]

I am using ITK 3.2. I should check out from the CVS then. Thanks!

On 7/5/07, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>
> Hi Won-Ki,
>
>
>
> 1) Yes, the effect of the filter should be equivalent
>    to applying smoothing, and following it with second
>    derivatives.
>
>
>
> 2) What version of ITK are you using ?
>
>
>    This problem was pointed out by Andreas Keil in the
>    users list on April 2007:
>
> http://public.kitware.com/pipermail/insight-users/2007-April/022019.html
>
>    We entered in the Bug tracker as Bug # 4934
> http://public.kitware.com/Bug/bug.php?op=show&bugid=4934
>
>    and committed a fix in the CVS repository on April 27th 2007:
> http://www.itk.org/cgi-bin/viewcvs.cgi/Code/BasicFilters/itkHessianRecursiveGaussianImageFilter.txx?root=Insight&sortby=date&r2=1.5&r1=1.4
>
>
>
>    You may want to update your CVS checkout version of ITK.
>
>
>    Please let us know if you still find any issues with
>    the current version.
>
>
>      Thanks
>
>
>        Luis
>
>
>
> ------------------
> Won-Ki Jeong wrote:
> > Hi all
> >
> > I have some questions about the HessianRecursiveGaussianImageFilter.
> >
> > Q1. Is this filter (theoretically) same as applying Gaussian smoothing
> > and compute derivatives to the input image? For example, let G be a
> > Gaussian kernel and I be the input image, then is the filter compute
> > (G*I)xx, (G*I)xy, (G*I)xz, (G*I)yy, (G*I)yz, (G*I)zz (subscript means
> > partial derivative along that axis)?
> >
> > Q2. If so, the implementation is not correct because, for example
> > (G*I)xx, the filter applies 1D recursive Gaussian order-1 derivative
> > filter twice along x and applies 1D recursive Gaussian filter along y,
> > that means along x the Gaussian is applied twice but there is no
> > Gaussian for z direction. Can somebody clarify this?
> >
> > The implementation is in void GenerateData(void) in
> > itkHessianRecursiveGaussianImageFilter.txx.
> >
> > Thanks a lot!
> >
> > Won-Ki
> > _______________________________________________
> > Insight-users mailing list
> > Insight-users at itk.org
> > http://www.itk.org/mailman/listinfo/insight-users
> >
>