[Mrtrix-discussion] information in the CSD file

[Donald Tournier]

Hi Nyoman,

Each volume of the CSD file contains one of the SH coefficients, as
documented on the csdeconv help page. When you say only the first 6 volumes
have contrast, do you mean the others are zero, or just look like noise? If
the latter, that's what you expect, since these volumes contain the l=4 and
higher harmonics, which are noisy. They still contribute high angular
frequency information though, and hence contribute to the angular
resolution - much like the outer edges of k-space contribute edge
information, even though they appear noisy.

Cheers,

Donald.


On 15 June 2012 17:51, Nyoman Kurniawan <nyoman.kurniawan at cai.uq.edu.au>wrote:

>  Dear Donald,
> Could you tell us what information is contained within each volume in the
> CSD files?
> For example, I used max harmonic order 6 and saw there are 28 volumes, and
> it looks that the first 6 volumes have some contrast?
>
> Regards,
> Nyoman
>
>
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-- 
Jacques-Donald Tournier (PhD)
Brain Research Institute, Melbourne, Australia
Tel: +61 (0)3 9035 7033
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