[Insight-developers] stack registration - links between optimizer scales, image intensity, size etc

[Richard Beare]

Hi,
It has been a long time since I played with the registration
framework, so I've forgotten how to deal with these issues (or never
knew).

I'm correcting a misaligned stack using 2d, pairwise, registration. I
have an old tool based on DeformableRegistration15 in itk 3.20 and a
newer one based on ImageRegistration7 in the itk 4.2 examples. The
latter works well for a large proportion of the stack and suddenly
produces a result with a very large incorrect angle. It produces that
incorrect angle after 1 iteration. The mean squared metric is used in
this example. Switching to Mattes MI without changing any parameters
produces crazy results.

Are there rules of thumb for setting optimizer scales and step sizes
based on the expected ranges of metric values and image sizes.

Thanks