[Insight-developers] Re: ImageMomentsCalculator

[Paul Hughett]

> I would like to make a rough guess for registering two volume datasets
> using Mutual Information. I nothiced that Paul has an
> ImageMomentsCalculator and also an
> ImageToImageMomentsAlignmentCalculator.  Does it make sence to use the
> latter. Seems that the transformn I get is much different than what I
> would expect.

I can claim credit for the first of those classes but not the second.
On a quick look, however, it seems that the transform returned by the
alignment calculator is from target principal axes coordinates to
reference principal axes coordinates.  What you would need to register
the reference image to the target coordinates would be the transform
from reference physical coordinates to target physical coordinates.
(And if I remember correctly, to resample the final result, you need
the transform from index coords to index coords.)

See also the PrincipalAxesResampler in the examples directory, which
resamples an image into its principal axes coordinates.

Paul Hughett