Hi,
Thank you very much. I still have a question. The original subject
image is epi sequence.After I transform this image to highres T1 image
and then to MNI-space, the intensity of the transformed sub2mni image
decreased compare to the original epi image. When transform, I use
trilinear interpolation and cost function is correlation ratio. How
can I improve this problem? Which interpolation method and cost
function should I apply?
Li
2008/1/21, Steve Smith <[log in to unmask]>:
> Hi,
>
> avscale gives you a whole set of different pieces of information about
> the spatial affine transform, including the average scaling (size)
> change. It does not tell you anything about intensities. On average,
> in general, intensities don't change upon resampling, though of course
> any given voxel will change!
>
> Cheers.
>
>
> On 19 Jan 2008, at 15:12, Li Jiang wrote:
>
> > Dear Steve Smith,
> >
> > I use fsl to process the functional MR data. It is a great software.
> > To process the data, I first transform the EPI (subject image) data
> > to T1 volume then to MNI_space with affine transformation. And I'll
> > measure the absolute value from the images have been coregistered to
> > MNI-space . I learned from the lectures and noticed the avscale for
> > Inter-subject Registration. I wonder what's the scale mean. If the
> > signal intensity of the subject image will change after affine
> > transformation or global intra-subject transformation.
> >
> >
> >
> > Best regards.
> >
> > Li Jiang
> >
>
>
> ---------------------------------------------------------------------------
> Stephen M. Smith, Professor of Biomedical Engineering
> Associate Director, Oxford University FMRIB Centre
>
> FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
> +44 (0) 1865 222726 (fax 222717)
> [log in to unmask] http://www.fmrib.ox.ac.uk/~steve
> ---------------------------------------------------------------------------
>
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