[Insight-users] Re: Multi Resolution Registration

[Luis Ibanez]

Hi Laia,


                        Welcome to ITK !


It should be possible to register, in about 5 minutes, images
of the size that you describe, using modern desktop computers.


You may want to give it a try to fine tune a normal single-resolution
registration before you move into the multi-registration framework.



A couple of questions:


   1) What is your platform ? (compiler, operating system)


   2) Did you make sure to build ITK in Release mode ?
      (a Debug build will be a lot slower).


   3) How are you initializing the Transform ?
      (starting with a poorly initialized transform will
       make very hard for the optimizer to find a solution
       in a short time).


   4) Did you produced a log of the transform parameters
      at every iteration of the optimizer ?
      This is very useful for fine tunning the parameters
      of the registration.



   Please let us know,


      Thanks


        Luis


-------------------
laia sales wrote:
> Hi All,
> 
> I am quite new in ITK and I am trying to use the Multi-Resolution 
> registration from ITK to register my images.
> 
> I am currently using CT images from femur bones of aproximately 
> 250x250x500 with different resolutions of around 0.6x0.6x0.1 mm.
> 
> The Optimizer, i am using is the itkVersorRigid3DTransformOptimizer and 
> the metric itkMeanSquaresImageToImageMetric.
> 
> I was firstly implementing the rigid registration with the code provided 
> with the 3D registration, and it resulted pretty slow. Therefore, I 
> wanted to try with the pyramidal registration to speed up the 
> registration, but it is not giving a faster process, but slowing down. I 
> don't get well the parameters SetMaximumStepLength and 
> SetMinimumStepLength. How these parameters can reduce the number of 
> iterations for each level and achieve a faster and optimal registration.
> 
> Does anybody use that kind of registration before and can give me some 
> hints abut it?
> 
> Regards,
> 
>