Dear Jung Lung,
According to your notation the file melodic_mix contains the
(pseudo)inverse of W, i.e. X = pinv(W) * C
X in this case is a txv matrix, where t denotes the number of time
points and v the number of voxels. This means that every component map
c_i together with the associated entry from pinv(W) totally describes
the 'dynamics' in 4D, i.e. the relative 'strength' of component 25 at
time point 50 is given by it's 50th coefficient in the associated time
course
hope this helps
Christian
Jung Lung Hsu wrote:
> Dear FSL expert,
> I have a question about the melodic result. As I know the ICA, if the X is
> data matrix and W is unmixing matrix and C is component matrix, than C =
> WX. My question is: the melodic_mix matrix is the W (unmixing matrix) or
> the inverted W ? another question is: Is it possible to view the component
> result in each time point ? I mean if I input a 4d analyze file which
> contain 100 3d image. Then it convert into 25 component. How to view the
> 12th component image in the 50th image (1-100 3d image)?
> thanks
> JLH
>
>
--
Christian F. Beckmann
Address: Oxford University Centre for Functional
Magnetic Resonance Imaging of the Brain,
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
Email: [log in to unmask] http://www.fmrib.ox.ac.uk/~beckmann/
Phone: +44(0)1865 222782 Fax: +44(0)1865 222717 Mob: +44(0)7811 189123
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