[Insight-developers] Allocation question

[Richard Beare]

Hi,
The output images are different types. I have overriden MakeOutput and
attempted to override AllocateOutputs, but didn't have any success.
Can you think of any filters that I might use as examples? I haven't
found anything yet.

On 10/11/06, Miller, James V (GE, Research) <millerjv at crd.ge.com> wrote:
> Richard,
>
> If your output images are different types, then you need to override the
> MakeOutput() method to create an image of the appropriate type for the
> mask.
>
> You may also need to override the AllocateOutputs() method to allocate
> the pixel data.
>
> Jim
>
> -----Original Message-----
> From: insight-developers-bounces+millerjv=crd.ge.com at itk.org
> [mailto:insight-developers-bounces+millerjv=crd.ge.com at itk.org] On
> Behalf Of Richard Beare
> Sent: Monday, October 09, 2006 10:05 PM
> To: insight-developers at itk.org
> Subject: [Insight-developers] Allocation question
>
> Hi everyone,
>
> I'm experimenting with a filter that takes two input images and produces
> two output images (class A). I'm adapting a threaded filter that uses
> two inputs and produces one output. I'm attempting to connect several of
> these together in a mini pipeline (class B).
>
> I'm having a problem causing the allocation of the second mask image to
> happen at an appropriate time.
>
> I have the following methods defined in class A:
>
> ThreadedGenerateData
> GenerateInputRequestedRegion
>
> I do the following in the constructor:
>
>   this->SetNumberOfRequiredInputs( 2 );
>   this->SetNumberOfRequiredOutputs( 2 );
>   this->SetNthOutput( 0, this->MakeOutput( 0 ) );
>   this->SetNthOutput( 1, this->MakeOutput( 1 ) );
>
> and have the following for setting/getting input and output images
>
>   void SetMaskImage(MaskImageType *input)
>      {
>      // Process object is not const-correct so the const casting is
> required.
>      this->SetNthInput( 1, const_cast<TMaskImage *>(input) );
>      }
>
>   /** Get the marker image */
>   MaskImageType * GetMaskImage()
>     {
>     return static_cast<MaskImageType*>(const_cast<DataObject
> *>(this->ProcessObject::GetInput(1)));
>     }
>
>
>   /** Get the modified mask image */
>   MaskImageType * GetOutputMask()
> {
>    return dynamic_cast<MaskImageType *>(
>     this->GetOutput( 1 ) );
> }
>   /** Get the result image */
>   OutputImageType * GetOutputImage()
> {
>    return dynamic_cast<OutputImageType *>(
>     this->GetOutput( 0 ) );
> }
>
> In my mini pipeline filter I have one instance per dimension, connect
> the two inputs of each filter to the outputs of the previous filter,
> with the first one in the chain being connected to the inputs of the
> meta filter.
>
> My problem is that the GenerateInputRequestedRegion for my class A
> filter is reporting that the mask image is null.
>
> So the question is where to perform the allocation? I've experimented
> with AllocateOutputs, and BeforeThreadedGenerateData, but without
> success. I've no luck tracking down a sample filter either.
>
> What is the correct place for this sort of thing to happen?
>
> Thanks
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