[Insight-developers] ImageToImageFilter: dimension reductionp
roblem
Miller, James V (Research)
millerjv@crd.ge.com
Fri, 26 Apr 2002 13:03:33 -0400
You change looks about right...
Since there is no data in the function object, it would be
hard to do any other type of comparison...
-----Original Message-----
From: Wilson Chang [mailto:wmcst6+@pitt.edu]
Sent: Friday, April 26, 2002 12:37 PM
To: Miller, James V (Research); Insight-developers (E-mail)
Subject: Re: [Insight-developers] ImageToImageFilter: dimension
reductionproblem
Jim
I've run into a snag calling this->SetRegionCopier(). As a test of the
SetRegionCopier, in itkExtractImageFilter I did the following typedef:
typedef
ImageToImageFilterDetail::ImageRegionCopier<InputImageDimension,
OutputImageDimension>
ExtractImageFilterDetailType;
ExtractImageFilterDetailType m_ExtractImageRegionCopier;
and in the constructor of itkExtractImageFilter I make the call:
this->SetRegionCopier(m_ExtractImageRegionCopier);
Basicly, as a test I tried to override the default RegionCopier with itself.
It becomes impossible to instantiate an ExtractImageFilter in my
application. Apparently, a stack overflow results, and it is related to the
!= operator in I2IFilterDetail:
/** operator!= for ImageRegionCopier objects. */
template<unsigned int D1, unsigned int D2>
bool operator!=(const ImageRegionCopier<D1, D2> &c1,
const ImageRegionCopier<D1, D2> &c2)
{
return c1 != c2; // THE LINE OF CODE IN QUESTION
}
apparently, it is calling itself in an infinite loop. this line of code
should be
"return &c1 != &c2" rather than "return c1 != c2"
right?
i'll check in the change if this seems correct to you.
wilson
----- Original Message -----
From: "Miller, James V (Research)" <millerjv@crd.ge.com>
To: "'Wilson Chang'" <wmcst6@pitt.edu>; "Insight-developers (E-mail)"
<Insight-developers@public.kitware.com>
Sent: Wednesday, April 24, 2002 1:36 PM
Subject: RE: [Insight-developers] ImageToImageFilter: dimension
reductionproblem
> What you want to do is define a new RegionCopier which is a subclass of
current
> RegionCopier that dispatches to appropriate overloaded routines (not
member functions)
> for the three cases (InDim = OutDim, InDim > OutDim, InDim < OutDim). This
will look
> similar to the current RegionCopier and delegated routines in the
I2IFilterDetail namespace.
>
> Then in the constructor of ExtractImageFilter create an instance of the
new RegionCopier
> and call this->SetRegionCopier().
>
> I tried to pattern the SetRegionCopier method off of how STL passes
function objects around.
> I haven't tried to use this method yet so I am not sure whether the
function object (RegionCopier)
> needs to be a pointer or not....
>
>
> -----Original Message-----
> From: Wilson Chang [mailto:wmcst6+@pitt.edu]
> Sent: Tuesday, April 23, 2002 5:38 PM
> To: Miller, James V (Research); Insight-developers (E-mail)
> Subject: Re: [Insight-developers] ImageToImageFilter: dimension
> reductionproblem
>
>
> hi,
> I havent been able to figure out how to use the SetRegionCopier() in the
> context of ExtractImageFilter. Specifically, how do i instantiate a
> subclass of the ImageToImageFilterDetail::RegionCopier function object to
> pass to SetRegionCopier()?
>
> This function object would be a function within ExtractImageFilter, and
> everytime a call to CopyRegion is made, it will dispatch to the function I
> passed to SetRegionCopier, right?
>
> thanks,
> wilson
>
>
>
> ----- Original Message -----
> From: "Miller, James V (Research)" <millerjv@crd.ge.com>
> To: "'Wilson Chang'" <wmcst6@pitt.edu>; "Insight-developers (E-mail)"
> <Insight-developers@public.kitware.com>
> Sent: Thursday, April 18, 2002 2:42 PM
> Subject: RE: [Insight-developers] ImageToImageFilter: dimension
> reductionproblem
>
>
> > I just checked in a series of changes to the architecture that allow
> > the output of a filter to be a different dimension than the input.
> > The difficulty in supporting this is that
> >
> > ImageToImageFilter::GenerateInputRequestedRegion()
> >
> > needs to be able to compile regardless of whether the input and output
> > dimensions match. The default implementation of this routine tries to
> > call
> >
> > input->SetRequestedRegion( output->GetRequestedRegion() );
> >
> > This line of code will not compile if the input region and the output
> > region are not the same dimension.
> >
> > In the new model, the line above is now
> >
> > InputImageRegionType inputRegion;
> > m_RegionCopier(inputRegion, output->GetRequestedRegion() );
> > input->SetRequestedRegion( inputRegion );
> >
> > m_RegionCopier is an ivar that is a function object. The call operator
> > dispatches to an overloaded function that is in NOT a member function
> > of ImageToImageFilter but rather is a standard function in a separate
> > namespace (thanks Brad!). Thus, the RegionCopier dispatches to one
> routine
> > if the input dimension matches the output dimension, another if the
input
> > dimension is less than the output dimension, and a third if the input
> > dimension is greater than the output dimension. The default
> implementations
> > are rather simplistic. If the input dimension is greater than the
output
> > dimension, the output region information is copied to the first part of
> the
> > input region. Zeros fill the remainder of the StartIndex and Size. If
> the
> > input dimension is less than the output dimension, the first part of the
> > output region is copied to the input region.
> >
> > If a filter needs a behavior different from this (for instance the
> > ExtractImageFilter should support a different behavior), the filter can
> > pass a different function object to ImageToImageFilter. This would
> > probably be done in the constructor of the filter. It would call the
> protected
> > method SetRegionCopier().
> >
> > The function object would have to provide the call operator and dispatch
> > to a different set of routines to handle the different behavior.
> >
> > To support these operations, there is a new file called
> > itkImageToImageFilterDetail.h that has a series of types defined to
> facilitate
> > dispatching to different routines based on dimensions.
> >
> > Brad also pointed out that the dispatch pattern currently deployed in
ITK
> > in a few places will have a problem with explicit instantiation. I'll
be
> > converting the current dispatch implementations to this new model.
> >
> > Wilson, you should be able to implement your filter to remove an image
> dimension.
> > I would suggest that functionality be placed in the ExtractImageFilter.
> >
> >
> >
> >
> >
> > -----Original Message-----
> > From: Wilson Chang [mailto:wmcst6+@pitt.edu]
> > Sent: Thursday, April 04, 2002 4:21 PM
> > To: Miller, James V (CRD)
> > Subject: Re: [Insight-developers] ImageToImageFilter: dimension
> > reductionproblem
> >
> >
> > Does it look like a fix to the base classes will be doable? If it isnt,
I
> > could do what luis was suggesting by having the dimension reduction
filter
> > inherit from process object.
> >
> > thanks,
> > wilson
> >
> >
> > ----- Original Message -----
> > From: "Miller, James V (CRD)" <millerjv@crd.ge.com>
> > To: "'Luis Ibanez'" <luis.ibanez@kitware.com>; "Wilson Chang"
> > <wmcst6@pitt.edu>
> > Cc: "Insight Developers" <Insight-developers@public.kitware.com>
> > Sent: Monday, April 01, 2002 8:36 AM
> > Subject: RE: [Insight-developers] ImageToImageFilter: dimension
> > reductionproblem
> >
> >
> > > I think there are a few ways that we can handle this.
> > >
> > > There already is a non-templated Region base class so that
> > > may be an avenue. Another option is to function overloading
> > > to force a default implementation when the dimensions
> > > match and require subclasses provided a method when the
> > > the dimensions do not.
> > >
> > > I'll put together a fix. Wilson, could you send me the
> > > snippet of your test program (or check in the test without
> > > putting it in the TestDriver yest) that is causing this
> > > error (just to save me from reinventing the wheel).
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: Luis Ibanez [mailto:luis.ibanez@kitware.com]
> > > Sent: Friday, March 29, 2002 5:15 PM
> > > To: Wilson Chang
> > > Cc: Insight Developers; Miller, James V (CRD)
> > > Subject: Re: [Insight-developers] ImageToImageFilter: dimension
> > > reduction problem
> > >
> > >
> > >
> > > Hi Wilson,
> > >
> > > The problem does not seem to be related with the
> > > run-time behavior of the virtual functions.
> > >
> > > What seems to happen is that regardless of how you overload
> > > the method in your code, the code of ImageToImageFilter<TI,TO>
> > > has to be compiled anyways and since the TInputImage
> > > and TOutputImage that are being used are not compatible
> > > the error will always appear at compilation time.
> > >
> > > In fact, the streaming itself is built on the assumption
> > > that dimension match. (Jim, please correct me if I'm wrong here)
> > > The only way around would be to have a RegionBase class, non
> > > templated from which Region derives, and then do the dimension
> > > checking at run time as opossed to compile time. The drawback
> > > here is the we will lose the performace of inlining Region related
> > > code and got the lower speed of virtual calls...
> > >
> > > Another option could be to add another ImageToImageFilter
> > > (with another name...) which just does not have methods
> > > relying on matching dimensions between the input and
> > > output.
> > >
> > > This is similar to the problem we encounter when we
> > > generalize the Transforms. Everything was fine until we
> > > got to the Perspective transform where the dimension
> > > of the output points do not match the dimension of the
> > > input points.... The solution taken in that case was to
> > > add the TransformBase (non-templated) class and
> > > afford virtual calls each time a point is transformed.
> > >
> > > One very short term solution for you could be to not derive
> > > from ImageToImageFilter but from ProcessObject.....
> > > but that may probably be only a temporary solution.
> > >
> > >
> > > Luis
> > >
> > > ====================================
> > >
> > > Wilson Chang wrote:
> > >
> > > > Hi, We have been working on a visualization project with itk and vtk
> > > > that requires having all of our images in 3-D or less. Therefore, I
> > > > have been working on a filter that reduces the number of dimensions
of
> > > > an image. This filter inherits from the ImageToImageFilter class.
> > > > The snag that I have run into is the GenerateInputRequestedRegion
> > > > function in the ImageToImageFilter class:
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > template<class TInputImage, class TOutputImage>
> > > > void
> > > > ImageToImageFilter<TInputImage,TOutputImage>
> > > > ::GenerateInputRequestedRegion()
> > > > {
> > > > ...
> > > >
> > > >
> > input->SetRequestedRegion(this->GetOutput()->GetRequestedRegion());
> > > > ...
> > > >
> > > >
> > > >
> > > > This line of code basicly requires that the input and output image
> > > > have the same number of dimensions. When I try to override this
> > > > GenerateInputRequestedRegion in my filter, I still get a compile
error
> > > > saying:
> > > >
> > > >
> > > >
> > > > cannot convert from 'const class itk::ImageRegion<2>' to 'const
class
> > > > itk::ImageRegion<3>'
> > > >
> > > >
> > > >
> > > > Is it possible that the superclass' definition of this function is
> > > > being called regardless of whether i've redefined this function?
> > > >
> > > >
> > > >
> > > > ideas?
> > > >
> > > >
> > > >
> > > > thanks,
> > > >
> > > > wilson
> > > >
> > >
> > >
> > > _______________________________________________
> > > Insight-developers mailing list
> > > Insight-developers@public.kitware.com
> > > http://public.kitware.com/mailman/listinfo/insight-developers
> > >
> >
>