Is there a way to prevent large deformations in BSpline transform?

[dzenanz]

BrainsFit has maxBSplineDisplacement parameter. Elastix' most similar parameter by name is DisplacementMagnitudePenalty, which does something completely different.

I already use TransformBendingEnergyPenalty, and it is helpful, but with very finely spaced control grid, I sometimes run into gradual growth/shrinking of some structures. In the screenshots below, left window is reference segmentation, right window is segmentation transferred by registration from another case. This happens only sometimes. What is the best way to deal with it?

Vertebrae are compressed in SI direction, and enlarged in other two axes. Face is squished in the LR axis.

[dzenanz]

How to add "incompressibility" and "rigidity" penalties described in elastix 2010 TMI paper?

[dzenanz]

Here is the other failing pair. The problematic deformations are rather localized.

[N-Dekker]

Indeed, elastix does not have such a feature, like "maxBSplineDisplacement". Sorry 🤷 Marius (@mstaring) suggested doing a multi-resolution registration, ensure that the grid size is not too fine, and use a small step size during optimization. Does that help you?

[dzenanz]

I will try to limit step size. I am already doing multi-resolution. Would it make sense to increase number of pyramid levels for the stage with finer grid?

[dzenanz]

Unfortunately, limiting maximum step size did not help in this scenario.