[Insight-users] Changes to CenteredEuler3D transform

[Karthik Krishnan]

jef vdmb wrote:

> Hi,
>
> I am working on a 3D registration, using 
> RegularStepGradientDescentOptimizer and CenteredEuler3DTransform. I 
> wrote a program using itk 1.8. Recently I upgraded to 2.4. When  
> trying to compile my old program with the new toolkit I got a 
> exception saying:
>
> Scales is set to 6, but NumberofParameters of the costfunction is 9
>
> There used to be 6 transformparameters for this transform. Does it now 
> have 9 (including the position of the center)? 

Yes.

> How does this affect the costfunction? What is the sequence of the 
> parameters (so I can set the scales correctly), or what do I have to 
> change to get my program working with itk 2.4?

At some point in your code, you would have the lines:

optimizer->SetScales( scales );
The scales should be an array of length 9 instead of 6.

PS:
I am not sure about the utility of optimizing both the center and the 
translation parameters in the transform.. It just seems like a waste, 
since one can achieve the other.. but you might want to play with it, 
using the scales to disable one of them to see if it helps.

>
> Thank you,
>
>
> Jef
>
>
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