[Insight-users] registration: time-consuming metric

[Jonathan Orban de Xivry]

Hello,

I'm currently working on deformable registration of RC-CT images in the
lungs. I'm using a mean square metric with a B-Spline interpolation (on a
6 by 6 by 6 grid ) in a 100*100*35 3D image. My computer is a pentium 4
working with Ubuntu 5.04 and ITK 2.2 version. The optimizer is a LBFGSB
and I've set the maximum number of iterations to 25.

The registration works well but takes more than an hour to perform the 20
to 25 iterations. I guess the metric is time consuming since it is
performed on the whole image. I've seen that the Mattes Mutual Information
metric allows to take samples in the image instead of taking all voxels.

Is there a possibility to do the same thing in other metrics as Mean
square or cross-correlation metric? Or do I have to implement it by
myself?

Thank you for your answer,

Jonathan