It isn't as simple as taking the FLIRT matrix and multiplying
by matlab coordinates. Either use img2imgcoord to convert
coordinates between spaces or generate the voxel to voxel
matrix (adjusted for the fact that matlab coordinates start
at 1, and nifti/fsl coordinates start at 0). You can find some
recent postings on the FSL list about the coordinate
conventions for FLIRT and how to generate voxel
mapping matrices in matlab.
All the best,
On 15 Aug 2009, at 08:14, Erlend Hodneland wrote:
> I have performed a registration between a fa image and an anatomy
> which works nicely. The transformation is saved in "mytrans.mat" as
> a 4x4
> matrix T.
> Now, I want to transform another object (some dti tracks) into the
> domain using the SAME transformation. I carry this out in Matlab, by
> multiplying T with the coordinates c = [x y z 1]' of my tracks
> c(anatomy) = T*c(dti)
> However, the tracks are slightly translated in one of the main
> directions(x,y or z). Have I missed something about the
> transformation and
> how it works? What can the problem be?
> Best regards
> Erlend Hodneland