[Insight-developers] example image to image filter with differentinput and output dimensions

[Miller, James V (Research)]

Simon, 

The UnaryFunctorImageFilter allows for the output image to have a larger
dimension than the input image.  Most of the code to handle this is in this
file.

Special code has to be put in the GenerateOutputInformation() method.  Also, 
you may need to be careful how you construct the regions for any iterators in
you GenerateData() methods.  Here is a snippet from UnaryFunctorImageFilter.  In 
this example, the outputRegionForThread was passed as a parameter to the
ThreadedGenerateData() method.  We have to use the CallCopyOutputRegionToInputRegion()
method to convert that region to a suitable region for the input.  This method is 
defined up in ImageToImageFilter.
 
  // Define the portion of the input to walk for this thread, using
  // the CallCopyOutputRegionToInputRegion method allows for the input
  // and output images to be different dimensions
  InputImageRegionType inputRegionForThread;
  this->CallCopyOutputRegionToInputRegion(inputRegionForThread, outputRegionForThread);

  // Define the iterators
  ImageRegionConstIterator<TInputImage>  inputIt(inputPtr, inputRegionForThread);
  ImageRegionIterator<TOutputImage> outputIt(outputPtr, outputRegionForThread);

I've used the CastImageFilter (a subclass of UnaryFunctorImageFilter) to increase
the dimension of an image.

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 Simon Warfield
Sent: Monday, October 10, 2005 9:25 AM
To: Insight-developers (E-mail)
Subject: [Insight-developers] example image to image filter with
differentinput and output dimensions



I am having some trouble with a filter that reads 3D data and generates 
4D data.
In particular, the default mechanism for constructing the 4D output 
fails with a bad cast error.

Are there any examples of image to image filters where the output 
dimension is larger than the input dimension ?

-- 
Simon


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