Integrate some remote modules into ITK proper

[dzenanz]

Some remote modules have been in use for a long time, and should be integrated into the main repository (i.e. https://github.com/InsightSoftwareConsortium/ITK/). Some examples are InsightSoftwareConsortium/ITKSplitComponents#50 and InsightSoftwareConsortium/ITKFastBilateral#2.

I think there are more, and we should review the complete list. Better candidates are the remote modules with just one or two filters.

Then there are some rarely used/unused ones, such as https://github.com/KitwareMedical/MultipleImageIterator. I think we should deprecate that one, and schedule it for removal in ITK6. Are there any more?

[dzenanz]

It would be appreciated if there are any volunteers for helping with this.

[hjmjohnson]

I would also vote for putting effort into the following to get them upto quality levels where they can be included in the toolkit:

AdaptiveDenoising
AnisotropicDiffusionLBR
GenericLabelInterpolator

MGHIO <--- On the fence about this one.

[dzenanz]

I thought that maintenance of MGHIO was shared with Slicer, and therefore isn't a good candidate for integration?

[hjmjohnson]

Slicer now uses MGHIO directly as an ITK remote module. Maintenance is done as an ITK remote module. I would think that adding it directly to the main repo would simplify the efforts of maintaining the codebase.

[dzenanz]

OK. It also doesn't have a lot of files, so it should be simple from that point of view.

I guess we could/should use a merge style which preserves file history for all the remotes we decide to merge.

[dyollb]

I would offer to help merge ITKLabelErodeDilate into ITK proper (if you agree it is a good candidate). Some instructions would be appreciated.

[dzenanz]

@dyollb maybe wait until we integrate one or two remotes in order to see how to do it.

[dzenanz]

Now is a good time to make these larger modifications.

[dzenanz]

Integrating remote modules which we intend to keep alive will simplify maintenance. There will be just one place to make sweeping changes, and it will be easier to check the scope of change/refactoring under consideration.

[dzenanz]

https://github.com/InsightSoftwareConsortium/ITKTBBImageToImageFilter should also be deprecated. It was superseded by Dynamic multi threading with TBB multi-threader back-end introduced in ITK 5.

[dzenanz]

Once we finish integration, we should put a note of some sort into the deprecated remote module repositories, so other people coming to them know what happened and don't spend time trying to use them.

[dyollb]

The GenericLabelInterpolator should be integrated. It's used in SimpleITK

[dzenanz]

Not all remote modules are mature to integrate into the ITK proper. But maybe we could merge some of them? E.g. merge all remote modules which are compute-only (do not depend on any external libraries) into a single one. How should we call it? External? Simple? Integrated? Merged? But not Review, as it would cause confusion with the built-in ITKReview.