[Insight-developers] SimpleITK: PDE Deformable Registration Straw man

[Bradley Lowekamp]

Hello,

I have been hacking away trying to add registration into SimpleITK. I have now prototyped up adding displacements fields and PDE base registration filters.

Here is my current working hacks:

https://github.com/blowekamp/SimpleITK/tree/STRAW-PDERegistration

And an IPython Notebook to demo:
http://erie.nlm.nih.gov/~blowek1/notebooks/SimpleITK_STRAW_PDE_Registration.html

This patch include the addition of the InvertDisplacementField filter along with the LevelSetMotion registration filter. Along with adding the capability to add displacement fields into a transform.

Along this path it should be easy to add the other "RegistrationFilters" such as Demons and Curves.

There are is one high priority issue that is needed to work in conjunction with this:

-Progress Reporting and Monitoring.

Additionally, there are a couple other issue:

- Adding optional inputs for the initial displacement field
- Adding named inputs

Also there is the issue of converting between VectorImages and Image of Vectors. The buffers are identical so I did some reinterpret_cast and buffer pointer manipulation to force it. It's not elegant, but there has been much effort in ensuring types like FixedArray and Vector, are nothing more than their data, so it should be well founded (Although it should use some type-traits validation). I am wondering if this should be more formalized and either as part of the CastImageFilter, or some ReinterpretImageFilter type of operation.

I am requesting feedback on the interface and usability etc.

Thanks,
Brad