[MINC-users] talairach volume and talairach center

[Jason Lerch]

Greetings,

the exact voxel coordinates are not going to tell you all that much
about the accuracy of the talairach registration. Odds are that you are
better off looking at the world 0,0,0 coordinates in some visualisation
tool like register or Display. I think that you'll find us being quite
close to the AC-PC line, though our registration procedure does not give
any special meaning to that point, so it is possible for it to be off by
a few millimetres even in a good registration.

Cheers,

Jason

On Thu, 2003-08-07 at 17:17, Yasunari Tosa wrote:
> Hi, MINC people
> 
> I'm very confused about the talairach coordinate system
> and I would appreciate it very much if you could clarify.
> 
> My question:
> Where is the talairach origin in the talairached volume?
> 
> I thought that average_305.mnc is the one aligned with
> talairach map (the web page says that it can be directly
> superimposed over the talairach atlas).  Thus I thought
> that this is the "standard" talairached volume.
> 
> When I did 
> 
> 	worldtovoxel average_305.mnc 0 0 0
> 
> returned non-trivial big values compared with the volume size.
> 
>     68.25 126.51000000000000512 86.094999999999998863
> 
> Here is the MINC linear map stored
> 
> MINC Linear Transform
>       1.0000      0.0000      0.0000    -86.0950
>       0.0000      1.0000      0.0000   -126.5100
>       0.0000      0.0000      1.0000    -68.2500
>       0.0000      0.0000      0.0000      1.0000
> 
> This means that the average_305 volume center is not the
> talairach origin.
> 
> Is this a correct understanding?
> 
> Thank you.
> 
> Tosa
> 
> 
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