[Insight-users] Mutual Information Question

[Tao Ju]

Hi,

I am new to ITK. I am currently working on registrating two slices of
nissl-stained brain images. Since the transformation involved would be
non-global, I tried out the FEM method for deformable registration and I
wanted to explore what Mutual Information could do. Here are some
questions:

1) First, by looking at the source code, it seems that the mutual
information image metric is NOT used in FEM deformable registration. In
FEM registration filter, it MIRegistrationFunction is loaded instead of
the MutualInformationImageToImageMetric. What's the difference between the
registration function and the metric? Are there any hints on picking
parameters for the MIRegistration function? Moreover, when I try to use
the image metric version of mutual information (by uncommenting the define
USEIMAGEMETRIC in itkFEMRegistrationFilter.h), the project fails to
compile.

2) Second, I used the FiniteElementRegistrationParameters1.txt
configuration file, as suggested by Luis. I magnified the
WidthOfMetricRegion parameter, but the program still jumps out after only
3 iterations. Are there other parameters that I need to set to make this
work?

3) What could be the best metric for registering two RGB color images with
white background?

Thanks!

Tao Ju