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ANTsX / ANTs

Advanced Normalization Tools (ANTs)
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providing initial transformation for Exponential transform #210

Closed vfonov closed 8 years ago

vfonov commented 9 years ago

If i run antsRegistration with --transform Exponential , the output Warp file is in log space, but then there is no way to specify this type of transform as initial-moving-transform or initial-fixed-transform

ntustison commented 9 years ago

the output Warp file is in log space

Can you elaborate further? Why do you think the output warp file is in log space? It's been a long time since I've looked at this so I'd like to know what you're looking at. Thanks.

ntustison commented 9 years ago

Also, just to follow-up, the warp field shouldn't be in log space. If it is, we'll need to correct it probably going all the way into ITK.

vfonov commented 9 years ago

ok, right now it is in log space - currently antsRegistration uses GaussianExponentialDiffeomorphicTransform , which is cast to DisplacementFieldTransform like here: https://github.com/stnava/ANTs/blob/master/Examples/antsRegistrationTemplateHeader.h#L1292

ntustison commented 9 years ago

I'm still not clear as to why you think it's in log space. The "transform" contained by the exponential transform is an actual displacement field describing the transform between spaces as in all the other displacement field transforms. This field is a result of integrating the class member constant velocity field (cf https://github.com/InsightSoftwareConsortium/ITK/blob/master/Modules/Filtering/DisplacementField/include/itkConstantVelocityFieldTransform.hxx).

stnava commented 9 years ago

​might be good to write out both the velocity field and the result of integration (which is standard displacement).​

brian

On Tue, Jul 21, 2015 at 3:02 PM, Nick Tustison notifications@github.com wrote:

I'm still not clear as to why you think it's in log space. The "transform" contained by the exponential transform is an actual displacement field describing the transform between spaces as in all the other displacement field transforms. This field is a result of integrating the class member constant velocity field (cf https://github.com/InsightSoftwareConsortium/ITK/blob/master/Modules/Filtering/DisplacementField/include/itkConstantVelocityFieldTransform.hxx).

— Reply to this email directly or view it on GitHub https://github.com/stnava/ANTs/issues/210#issuecomment-123490586.

ntustison commented 9 years ago

Yeah, we do it for the time varying cases

https://github.com/stnava/ANTs/blob/master/Examples/antsRegistrationTemplateHeader.cxx#L27-L35

Would be just as easy to do it for the constant velocity field cases.

vfonov commented 9 years ago

Ok, I might have got confused.... I will make changes to save velocity field

ntustison commented 8 years ago

Closing this for now. Might want to revisit.