[Insight-users] Subclassing ImageToImageFilter

[Soren Christensen]

Many thanks!
I'll give vector images a shot - it sounds like the obvious solution.
Great to know abut the new regionsplitting functionality too, so thanks for
the detailed answer. I am using 4.3 btw.


Soren


On Thu, May 2, 2013 at 6:04 AM, Bradley Lowekamp <blowekamp at mail.nih.gov>wrote:

> Hello,
>
> The wiki examples are a wonderful resource put together by the community!
> With some very dedicated individuals.
>
> To me is sounds like you are dealing more with 3D image of vector as
> opposed to 4D images. I would look into using a VectorImage for image
> input, this image class allows for variable number of components. For the
> output I'd look into an Image of FixedArray, Vector etc..
>
> What version of ITK are you using? If you really do need true 4D images,
>  then some important changes have happened in ITK. Just in the past month I
> have modularized how image region splitting is performed in many areas of
> ITK include threading. Basically, there is a new ImageRegionSplitterBase[1]
> class that can be plugged into filter to changes how images a split for
> multi-threading.  The ImageRegionSplitterSlowDimension contains the code to
> split images that was in the ImageSource. There is now a
> ImageSource::GetImageRegionSplitter[3] method which returns the object used
> to perform the splitting for multi-threading. This can be overloaded to
> return the appropriate splitter object for the algorithm implemented in a
> filter. An example of this is in the RecursiveSeparableImageFilter[4]. It
> uses the ImageRegionSpliterDirection class to split is a specified
> direction. For yourself you could specify dimension direction 2. From there
> is should be easy to define the input region from the outputRegionForThread
> to accomplish what you wish.
>
> Hope this bit of a tangent helps,
> Brad
>
> [1]
> http://www.itk.org/Doxygen/html/classitk_1_1ImageRegionSplitterBase.html
> [2]
> http://www.itk.org/Doxygen/html/classitk_1_1ImageRegionSplitterSlowDimension.html
> [3]
> http://www.itk.org/Doxygen/html/classitk_1_1ImageSource.html#ab009a02af33d02e6d5376cb1fb0efe05
> [4]
> https://github.com/Kitware/ITK/blob/master/Modules/Filtering/ImageFilterBase/include/itkRecursiveSeparableImageFilter.hxx#L190
>
> On May 2, 2013, at 2:32 AM, Soren Christensen <sorench at gmail.com> wrote:
>
> Hi,
>  I am trying to create a filter using ImageToImageFilter that I would like
> to be multi-threaded.
> However, I have some trouble figuring out how to get the dimensions right.
>
> The input is 4D and I want to create an output that is also 4D, but the
> fourth dimension of the output will always be of constant length in the
> output, say L=4. (So Dim4 is a vector dim and regardless of the input
> length the outputs 4th dimension will have length 4).
> In ThreadedGenerateData(), I would like to just iterate spatial positions
> (the first 3 dimensions) so for example partition the
> outputRegionForThread partitioned along the 3rd dimension (although along
> 1 or 2nd dim would work too).
> So essentially I want to iterate over all spatial locations (dimensions
> 1-3), and for each spatial location grab the vector along the 4th
> dimension. For each location, the result (vector of length 3) is written
> into the 4D output.
>
> It seems to me that once I define the output dimensions in GenerateOutputInformation()
> (4D), then ThreadedGenerateData() will partition THIS 4D region whereas I
> am looking to iterate just the first 3 dimensions of the output.
> How can I achieve this?
> Should I be looking at using vector images for this?  Or multiple outputs?
>
> Thanks
> Soren
>
>
> Btw:
> Thanks to whoever put all the examples on Wiki  - they are fantastic.
>
>
>
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