[Insight-users] Compute joint histogram after registration

[Yan Yang]

Hi All,

I realized that the transform in optimization is the one mapping from fixed image space into the moving image space. 

But I think the transform result computed by the registration framework should transform the moving image into the fixed image space, this means the parameters got from the method 
registration->GetLastTransformParameters()
should be in different direction from the transform direction in optimization. Am I right?

I want to compute the joint histogram after registration, so I have to use the transform computed by registration to get overlapped points. Can I do it in the way as the following?

1. Walk through all the voxels in the fixed image,
2. transform each voxel index in the fixed image into a physical point (inputPoint)
3. transform the point "inputPoint" using the transform parameters got from the method "registration->GetLastTransformParameters()", and get the "transformedPoint" in the moving image space;
4. transform the "transformedPoint" into an index of the moving image, and compute the grey value by interpolation;
5. add frequency to histogram according the grey value pair in the fixed and moving image;

I want to know if I used the correct tranform parameters - mapping from fixed image space into moving image space, is "registration->GetLastTransformParameters()" the right one?

Many thanks,

Yan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://public.kitware.com/pipermail/insight-users/attachments/20060704/9b09fd43/attachment.html